[regression] Fix resource refreshes after git operations
The asynchronous RepositoryChangeScanner must _not_ trigger synchronous refreshes. It uses a non-resource scheduling rule and thus must not perform any workspace operations. Re-introduce the ResourceRefreshJob but let it use the new ResourceRefreshHandler. Re-add merging of events, and re-introduce IProgressMonitor so that the UI bundle can cancel its jobs when being stopped.
Bug: 551289 Change-Id: I961ff20355baf7e3d88d2ca222b937f7ffd43fb6 Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>