Add an explicit Refresh Metadata that doesn't need to retrieve metadata describes at all

From Oleg Demchenko:

When I start "Retrieve Metadata" and before I can choose "Selected" - Illuminatedcloud loads metadata describes for connection - and it takes a lot of time for huge metadata packs. As for me good decision is to select files in "Project" area, right-click, "Illuminated Cloud -> Reload selected from server" and it just quickly reloads selected files.