samba: Remove option to backup app
Reasons:
- Privileged action security: restoring Samba configuration from a backup file could expose any folder in OS and allows to run any commmand as a root user.
- Samba backups aren't so useful as only app configuration is included. Configured shares are trivial to enable without backups. Also, providing backups could be misleading as stored user files aren't actually backupped.
Tests performed:
- All Samba functional tests pass.
- Restoring from an old backup that also includes Samba is not failing, restoring Samba is skipped.
Signed-off-by: Veiko Aasa veiko17@disroot.org