Review the communication between Drive and the FinderSync extension

It seems that when several Finder windows are opened at the same time on a synced folder containing 100+ files, if we open Drive, there might be a crash of the extension, and sometimes even Drive. We should identify the bottleneck and find options to handle it or at least mitigate it.
Solution: we're requesting statuses per folder, so that there is only one connection per folder consulted in the Finder, and Drive can send the status for all the files directly contained in it.
Also the extension wasn't starting/stopping with Drive, so there are extra pluginkit commands to get it to run at the right time.