Reimplement lost commit, refactor...
Description
Forgotten commit due to local issue with git for issue 1290
- some refactoring of Synchronization service.
Screenshots
Technical details
- Remove "RemoveFileOperation"
- Remove SyncRequest type: remote_delete
- improving logging in SynchronizationService
- Add missing instruction about failure counter
Tests
Issues
https://gitlab.e.foundation/e/os/backlog/-/issues/1290