Talos: Upgrade node-gyp to v7 (and more)

We were using node-gyp v3.8.0, which has a bug preventing it to be used with Python3
However, we build on Alpine Linux, which requires Python3.

As the bug was showing up while building node-sass,
the later was also updated to a compatible version.
It also helps as the node-sass version was ancient and did not
work with all recent node.js versions.

However, as `react-scripts` depended on `sass-loader` v8,
and `sass-loader` depends on `node-sass` v4.x.x, we also had to bump `react-scripts`.
The first version to support `sass-loader` v11 was v4.0.2 and v4.0.3 is the latest
version as of the time of this commit.

This then led to facebook/create-react-app#9937
which is worked around by simply moving the assets.

package.json

@@ -10,14 +10,15 @@
     "axios": "^0.19.2",
     "clsx": "^1.1.0",
     "lodash": "^4.17.15",
-    "node-sass": "^4.13.1",
+    "node-gyp": "^7.1.2",
+    "node-sass": "^5.0.0",
     "react": "^16.13.1",
     "react-custom-scrollbars": "^4.2.1",
     "react-customize-token-input": "^0.5.2",
     "react-dom": "^16.13.1",
     "react-input-mask": "^2.0.4",
     "react-redux": "^7.2.0",
-    "react-scripts": "3.4.1",
+    "react-scripts": "^4.0.3",
     "rebound": "^0.1.0",
     "redux": "^4.0.5",
     "redux-logger": "^3.0.6",

src/components/preview/preview.module.scss

@@ -130,7 +130,7 @@
     }
 
     .container_sideLeft {
-      background-image: url(/img/main_background.svg);
+      background-image: url(/assets/img/main_background.svg);
       @include back-img(inherit, right top, no-repeat);
       display: flex;
       justify-content: end;
@@ -151,7 +151,7 @@
         height: auto;
         min-height: auto;
         display: block;
-        background-image: url(/img/index-back.svg);
+        background-image: url(/assets/img/index-back.svg);
         @include back-img(cover, left bottom, no-repeat);
       }