Fixes for missing configuration for TGCs in some places, and handle the fact that TGC ELs are broken in some files (ATLASRECTS-5151)

Cleaned up TrackEventCnvTool (making the sub-tools private, for example).
Added a new ability to MuonEventCnvTool to fix ATLASRECTS-5151 (and configured this on in the two main reco sub-steps in MuonConfig).
Made MuonEventCnvTool a friend of TGC ROT (not strictly necessary, but cleaner)