Standard resolutions for file conflicts

### Is your feature request related to a problem? Please describe.

For some reasons, the App keeps complaining about file conflicts when doing the intial sync of the photos from the phone to the server. This means multiple taps for each conflict to solve manually.

### Describe the solution you'd like

In Settings, give a configuration option how to solve file conflicts by default ("always server file" or "always local file").

Make it easier to resolve a row of conflicts other than manually clicking through individual notifications that lead to a slowly responding App page.