Allow the user to set an option to automatically fix file conflicts

### How to use GitHub

* Please use the 👍 [reaction](https://blog.github.com/2016-03-10-add-reactions-to-pull-requests-issues-and-comments/) to show that you want to have the same feature implemented.
* Please don't comment if you have no relevant information to add. It's just extra noise for everyone subscribed to this issue.
* Subscribe to receive notifications on status change and new comments.

### Feature description
Tell us how the feature should work
Have an per-user option that allows the user to set Nextcloud to automatically keep the local copy of a file, or download and replace the conflicting version off the server.