Clean up refinery and harvester docking sequence logic

This has been bugging me for a long time now, so I finally decided to address it.
@Phrohdoh mentioned a few days ago on IRC that he wants to do some work on refineries, so if this is conflicting with his work we'll just close it for later (if needed), since it's not a feature or a bug fix.
Basically what I did:
 - Rename TiberiumRefinery -> TiberiumDawnRefinery (only Tiberian Dawn mod uses it)
 - Rename HarvesterDockSequence -> TDHarvesterDockSequence (same reason)
 - Rename OreRefinery -> Refinery  (since both RA and Dune 2000 mods uses it)
 - Rename RAHarvesterDockSequence -> HarvesterDockSequence  (same reason)
 - Fixed a typo in RefineryInfo's DockAngle's description
It will eventually find its way into `OpenRA.Mods.Common`. But for the moment it's stuck in `Mods.RA` because it inherits from `HarvesterDockSequence` which is currently not so easy to move. Perhaps that would be the goal of my next file movement PR.