feat(theseus): Update to Tauri v2

[Norbiros]

This PR updates codebase to use Tauri v2 and cleans up some code.

Progress

• Make Theseus work with Tauri v2
• Allow scaling UI
• Reduce boilerplate in plugins.json - waiting for Apply Version Updates From Current Changes tauri-apps/tauri#10685
• Test everything (mostly deeplinks on mac & other platforms)
• Update Github Actions to use webkit 4.1
• Fix App Release github action - (depends on Yarn isn't detected with workspace setup tauri-apps/tauri-action#161, but fixed in different way)
• Fix MacOS & windows builds
• External links open in app instead of browser (Probably requires custom script or modification to shell plugin's code)
• Improve build.rs - waiting for [feat]: Reduce boilerplate for command definitions in Tauri v2 tauri-apps/tauri#10075
• Clean up plugins (only partially done auth and login) - will be done in separate PR

Closes

Resolves #1230
Resolves #214
Resolves #995
Resolves #520
Resolves #239
Resolves #867
Resolves #991
Resolves #1065

[getchoo]

Thanks for getting rid of the git dependencies here, it'll help a lot with packaging! Please let me know if there's anything you need help with :)

[Norbiros]

I believe most of the work is complete. I'll clean up the plugins in a future PR. I've tested the app only on Linux, so it would be great if someone could test it on other platforms and confirm that it works.

@Geometrically, please rename TAURI_PRIVATE_KEY to TAURI_SIGNING_PRIVATE_KEY for workflow to pass.

[jebibot]

Please note in @tauri-apps/plugin-dialog@2.0.0-rc.0, open returns a FileResponse object instead of a string for the file selection. However, this behavior is reverted in tauri-apps/plugins-workspace@448846b#diff-7d692d06c9825847f618edbc332bca2f7196f2495e86f2a80825d0d9b76a6d51, which has not been released yet, so there would be no need to change the code, but the file selection wouldn't work until a new version is published and updated.