Ability to backup / restore app settings

I do occasional ROM tests and it is always pain to restore Nextcloud app to working order - mostly several auto-upload folders I use which are (nearly) always the same. I use SeedVault for most of my backups but NC doesn't allow backup.

An obvious solution for a _cloud_ app would be, to, err, store its settings in the cloud :) App can export the settings and save it in the connected NC instance in the same way contacts and calendars are backed up.

Alternative solution (and simple from code perspective) would be to allow the app to have its data backed up by Android backup provider, which is now disallowed.

A poor man's fix might be adding a "export/import settings" option in settings, though this is essentially the same as the first suggestion.