Struct variant for WebView on macOS 13 Ventura

[obvgab]

Description

This PR fixes the NSViewRepresentable value type issue for WebView on macOS Ventura. Similar to #135, just applying the same idea to WebView.

A few notable things:

• WebView variables had to be marked with @State to avoid struct immutability
  • To not change state values during view updates, most mutating operations use DispatchQueue().asnyc { }
  • Not entirely sure how this affects how the code runs, seems to be the same
• Is it necessary to use if #available(macOS 13, iOS 16, *)? Is there any reason to keep the class version?
• iOS 16 might have the same issue. Preliminary code is in place, but I don't have swift-bundler for iOS
  • Does #135 fix it on iOS?

Type of change

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation comments
• [ ] My changes generate no new warnings
  • [x] Tested on macOS
  • [ ] Tested on iOS

[stackotter]

Is there any reason to keep the class version?

I honestly don't remember, I just tried on my laptop (macos 12) and it works without the class version 🤷‍♂️ once @ninjadev64 tries out the app without the class on big sur we can probably just remove both of the classes (MetalViewClass and WebViewClass) if all goes well

[stackotter]

Unfortunately Microsoft has changed their authentication flow and the way Delta Client was doing it no longer works. Therefore I've merged in some changes I made ages ago (on a separate branch) that was test driving Microsoft's device code based authentication, and for now that doesn't use a webview at all. So sadly these changes will be superseded as soon as I merge the linux branch in main.

However I'm happy to merge the PR if you would like to show up in the contributors list for helping out anyway :) because your changes would still be useful if we ever change back to a webview-based login flow for Microsoft accounts (which is a likely possibility knowing Microsoft). Alternatively I can give you the contributor role on Discord anyway. It's just unfortunate timing of events, why does Microsoft just breaks things like this 😠

[obvgab]

Seems like the timing was just too late. And don't worry about the contributors list--I'll just help somewhere else in the repository for it 😄