When an Update Level (UL) is upgraded to, Evergreen should automatically go to the previous version if Jenkins isn't available after restart.

Acceptance Criteria

Updating to an UL that prevents Jenkins from starting again should automatically trigger going back to a working UL.

NOTE: The Data snapshotting part, especially useful if a plugin has changed its data format, will not be handled here. We will solely focus on the UL and global list of things to "go to".