Steal Objectives Update

**This is a remake of https://github.com/tgstation/-tg-station/pull/453 after git imploded on itself.

-Removed head jumpsuits from the steal objectives list, as they were hardly taken seriously.
-Added Medal of Captaincy to list of steal objectives
-Readded Nuke Disk to list of special steal objectives. I've tested it and it DOES work.
-Grammar fix for special steal objectives
-Updated changelog