feat: add desktop app package

[Vexcited]

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This is still a draft though but here's what we got (as discussed in the discord group chat)

• Titlebar implementation in client - we show it only if we use the frontend with Tauri
• Modify some scripts to include building desktop
• Add a section about building/dev for the desktop app in README
• System tray
  • Quit
  • Hide
  • Show
• Updater
• Keep running in background (when hiding/closing window) until quitted
• Start automatically with system
• Store app configuration about start automatically, close behavior, etc... when changing in settings (have to wait until settings menu is done/drafted)
• Notifications

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[Vexcited]

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[Vexcited]

recheck

[insertish]

I think Zomatree wants to pick this up, probably best to merge and split stuff into separate issues.
NB. assets need to be removed before merge

(I will attempt to merge this soon)

Note to self: revoltchat/components#1