MuonCombinedEventStoreAlgs, etc: Remove MuonTrackSlimmer
requested to merge ssnyder/athena:noMuonTrackSlimmer.MuonCombinedEventStoreAlgs-20191121 into master
MuonTrackSlimmer operates on the run 1 EDM and is in fact never enabled anywhere in the current release.
Remove it, in order to allow eventually removing the old thinning service.