Adjust app icons to support HomeScreen tinting on iOS 18 (#3680)

Task/Issue URL:
https://app.asana.com/0/1206226850447395/1208303061602073/f
Tech Design URL:
CC:

**Description**:

Moving app icons to assets in order to support iOS 18 tinting on Home
Screen. There were a few issues, which look like a bug or inconsistency
in iOS:
1. It wasn't possible to load app icon asset as `UIImage`, thus I needed
additional separate images for display on UI. I tried out [Apple's
sample
project](https://developer.apple.com/documentation/xcode/configuring_your_app_to_use_alternate_app_icons)
and it also failed to display app icons.
2. I left updated icons definitions in `Info.plist` even though the
functionality did work without them. It seems those values are included
by compiler, but without having those predefined, the Alpha build app
icon was used throughout Xcode UI.

I removed multiple variants for each AppIcon asset and left only a
single image of 1024px size. Starting from Xcode 14 asset catalog can
use this size to autogenerate all other required sizes.

**Steps to test this PR**:
1. Run the app 
2. Test each icon color is displayed properly on Home Screen, task
switcher, folder in app library
4. Turn on tinted mode in Home Screen customization menu, verify icons
are properly tinted
5. Check if switching icon variants works on iPad.

**Definition of Done (Internal Only)**:

* [x] Does this PR satisfy our [Definition of
Done](https://app.asana.com/0/1202500774821704/1207634633537039/f)?

**Device Testing**:

* [x] iPhone SE (1st Gen)
* [ ] iPhone 8
* [ ] iPhone X
* [x] iPhone 14 Pro
* [x] iPad

**OS Testing**:

* [x] iOS 15
* [ ] iOS 16
* [x] iOS 18

**Theme Testing**:

* [x] Light theme
* [x] Dark theme

---
###### Internal references:
[Software Engineering
Expectations](https://app.asana.com/0/59792373528535/199064865822552)
[Technical Design
Template](https://app.asana.com/0/59792373528535/184709971311943)

DuckDuckGo/AlternateAppIcons.xcassets/AppIcon-black.appiconset/Contents.json

@@ -0,0 +1,38 @@
+{
+  "images" : [
+    {
+      "filename" : "Icon-Color-Black-1024x1024.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "filename" : "Icon-Color-Black-Dark-1024x1024.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "tinted"
+        }
+      ],
+      "filename" : "Icon-Tinted-1024x1024.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

DuckDuckGo/AlternateAppIcons.xcassets/AppIcon-blue.appiconset/Contents.json

@@ -0,0 +1,38 @@
+{
+  "images" : [
+    {
+      "filename" : "Icon-Color-Blue-1024x1024.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "filename" : "Icon-Color-Blue-Dark-1024x1024.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "tinted"
+        }
+      ],
+      "filename" : "Icon-Tinted-1024x1024.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

DuckDuckGo/AlternateAppIcons.xcassets/AppIcon-green.appiconset/Contents.json

@@ -0,0 +1,38 @@
+{
+  "images" : [
+    {
+      "filename" : "Icon-Color-Green-1024x1024.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "filename" : "Icon-Color-Green-Dark-1024x1024.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "tinted"
+        }
+      ],
+      "filename" : "Icon-Tinted-1024x1024.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

DuckDuckGo/AlternateAppIcons.xcassets/AppIcon-purple.appiconset/Contents.json

@@ -0,0 +1,38 @@
+{
+  "images" : [
+    {
+      "filename" : "Icon-Color-Purple-1024x1024.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "filename" : "Icon-Color-Purple-Dark-1024x1024.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "tinted"
+        }
+      ],
+      "filename" : "Icon-Tinted-1024x1024.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

DuckDuckGo/AlternateAppIcons.xcassets/AppIcon-yellow.appiconset/Contents.json

@@ -0,0 +1,38 @@
+{
+  "images" : [
+    {
+      "filename" : "Icon-Color-Yellow-1024x1024.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "filename" : "Icon-Color-Yellow-Dark-1024x1024.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "tinted"
+        }
+      ],
+      "filename" : "Icon-Tinted-1024x1024.png",
+      "idiom" : "universal",
+      "platform" : "ios",
+      "size" : "1024x1024"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

DuckDuckGo/AlternateAppIcons.xcassets/Contents.json

@@ -0,0 +1,6 @@
+{
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

DuckDuckGo/AlternateAppIcons.xcassets/UIAssets/AppIcon-black-medium.imageset/Contents.json

@@ -0,0 +1,54 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "filename" : "AppIconBlack60x60@2x.png",
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "filename" : "Icon-Color-Black-Dark-120x120.png",
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "AppIconBlack60x60@3x.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "filename" : "Icon-Color-Black-Dark-180x180.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

DuckDuckGo/AlternateAppIcons.xcassets/UIAssets/AppIcon-black-small.imageset/Contents.json

@@ -0,0 +1,54 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "filename" : "AppIconBlack29x29@2x.png",
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "filename" : "Icon-Color-Black-Dark-58x58.png",
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "AppIconBlack29x29@3x.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "filename" : "Icon-Color-Black-Dark-29x29.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

DuckDuckGo/AlternateAppIcons.xcassets/UIAssets/AppIcon-blue-medium.imageset/Contents.json

@@ -0,0 +1,54 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "filename" : "AppIconBlue60x60@2x.png",
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "filename" : "Icon-Color-Blue-Dark-120x120.png",
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "AppIconBlue60x60@3x.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    },
+    {
+      "appearances" : [
+        {
+          "appearance" : "luminosity",
+          "value" : "dark"
+        }
+      ],
+      "filename" : "Icon-Color-Blue-Dark-180x180.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}