Enable Seedvault backups

[PandaCoderPL]

Is your feature request related to a problem? Please describe.
No

Describe the solution you'd like
In my opinion it would be good idea to let users backup TRIfA application using Seedvault. Here you can see example of how such backup option could be implemented in privacy-respecting way. More details about it here. Thank you in advance.

Your system information:

• TRIfA Version: 1.0.123
• App from Google-Play / F-Droid / Github-Releases / other: F-Droid
• Android OS Version: Android 12 (GrapheneOS)
• Device: Google Pixel 4a

Describe alternatives you've considered
If enabling Seedvault backups is not possible for any reason then implementing #307 would be better than nothing.