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
One of our primary [development goals](https://github.com/OpenRA/OpenRA/wiki/Development-Goals) is to create a highly flexible engine for downstream modders.  Third party mods can include their own dlls with new traits, but can't modify anything in our core assemblies.

Many of the design decisions that might otherwise look strange or unclean are motivated by this goal.