Clean up Tauri

[dscso]

The following changes:

• path_trav had to be removed
  • path traversal is prevented by not allowing certain characters in the filename
  • path_trav uses fs::canonicalize internally, which always fails if a file does not exist => not suited for our needs
• tauri notification replaced with mac-notification-sys
  • this has the advantage of further modification to allow the user to reply on messages directly in the notification
  • Notification Listeners for Mac and Windows hoodie/notify-rust#186
• file download supports progress
  • a callback can be registered when starting the download (see below)
• set badge count is supported by setBadgeCount(count: number)
  • app needs to be packaged for this to work
• this.__isApp = !this.__isBrowser was replaced with this.__isApp = window.__TAURI__ !== undefined
  • the old version was not working

await UtilitiesRuntime.requestFileDownload(
  event.file.url,
  event.file.name,
  (current, total) => console.log(`${Math.round(current/total*100)}% done`)
);

[dscso]

a57ed39 adds support for deep linking. If the application is compiled and placed in the /Applications folder, Prose registers as a opener for xmpp:// URLs