More efficient handling of local file copies

Current Behavior

As seen with NXDRIVE-1714, 1,971,026 FS events are generated while doing the copy of a 100 GB into the local sync folder.
This is the now critical part of the process as each event create a lot of work for Drive and the OS.

The main impact for the end-user is that the upload does not start directly after the copy is finished: there is a significant delay (here 15 minutes). This is the time taken to process those events.

There may be some room of improvement here, but it is not so easy as skipping such events will break a lot of things in the sync engine (like conflicts detection, file change while downloading or uploading the same file, ... ).

New Behavior

Making use of the local events queue (NXDRIVE-2540), such events could be ingested and one final FS event should be put into the LocalWatcher queue: the final file created event.