[iOS][macOS] Rework top-level file management

[mischreiber]

Platforms Impacted

• iOS
• visionOS
• macOS

Description of changes

High-level summary of changes to structure:

Before:

.
├── Demo
├── ios
│   ├── FluentUI
│   ├── FluentUI.Demo
│   ├── FluentUI.Resources
│   └── FluentUI.Tests
├── macos
│   ├── FluentUI
│   ├── FluentUIResources-macos
│   ├── FluentUISwiftUITestApp
│   ├── FluentUITestApp
│   ├── FluentUITestViewControllers
│   └── FluentUIUnitTest
├── public
│   └── FluentUI.swift
└── scripts

After:

.
├── Demos
│   ├── FluentUIDemo (SwiftUI WIP)
│   ├── FluentUIDemo_iOS
│   └── FluentUIDemo_macOS
├── Sources
│   ├── FluentUI
│   │   └── FluentUI.swift
│   ├── FluentUI_iOS
│   │   ├── Core
│   │   ├── Components
│   │   └── Resources
│   ├── FluentUI_macOS
│   │   ├── Core
│   │   ├── Components
│   │   └── Resources
│   └── FluentUI_common (name TBD)
├── scripts
└── Tests
    ├── FluentUI_iOS_Tests
    └── FluentUI_macOS_Tests

Binary change

n/a - no changes to build output

Verification

• Full build and test pass of both libraries
• Built release schemes for both libraries
• WIP: Podspec validation

Pull request checklist

This PR has considered:

• Light and Dark appearances
• iOS supported versions (all major versions greater than or equal current target deployment version)
• VoiceOver and Keyboard Accessibility
• Internationalization and Right to Left layouts
• Different resolutions (1x, 2x, 3x)
• Size classes and window sizes (iPhone vs iPad, notched devices, multitasking, different window sizes, etc)
• iPad Pointer interaction
• SwiftUI consumption (validation or new demo scenarios needed)
• Objective-C exposure (provide it only if needed)

Microsoft Reviewers: Open in CodeFlow

[joannaquu]

can we also update the readmes/contributing.md. I just went through them and some still point to the xcodeproj oops.

[Saadnajmi]

Dumb question: Is cocoa pods still supported after this?

[joannaquu]

I believe our localization script also needs updating

[joannaquu]

all our doc links will also be broken but maybe for another pr?

[mischreiber]

Dumb question: Is cocoa pods still supported after this?

@Saadnajmi not dumb! Yes, I made extensive changes to the podspec in commit c3a919f to keep it building.

[mischreiber]

@joannaquu updating docs, loc script, and readme now