Add trackfinding new config to MuonConfig

There are a LOT of FIXME and TODOs in here ... please don't ping me on this as this is the first attempt at Track Building with the new configuration, and I am flagging issues as I spot them so I can come back later i.e. I really, really do want to have lots of comments in for the moment, but I will clean it all up in a later MR once I'm sure it's correct.