sync folder -> auto upload + delete

### Is your feature request related to a problem? Please describe.
I'm trying to backup my Signal Backups. So I set up auto upload. Signal keeps only two backup-files in local folder (deleting older files), Nextcloud keeps adding, so I have to manually delete older ones.

### Describe the solution you'd like
Keep folder in sync instead

### Describe alternatives you've considered
Upload complete folder once every x day at xx:xx (if charging) and delete older versions of this folder after x days or successful backups.

### Additional context
If I was to backup a folder like downloads there would be a hole lot of crap inside if it does not delete anything and instead keeps ever file that has ever been in this folder