Automatic backup and restore

[DennisBauer]

Is your feature request related to a problem? Please describe. Manual backups can be out of date and an automatic sync e.g. through Nextcloud can't be achieved.

Describe the solution you'd like Add an option in the settings to create a new backup whenever the database updates (any change to the expenses).

Describe alternatives you've considered, if any Scheduled backups in a fixed time frame, but it doesn't really make sense to create a backup when nothing changed.

Additional context