Major dev update: unused detectors removal + build with apr21 Fairsoft version

Ready to be merged into dev.

OLD DEV COPY IS IN THE BRANCH dev_june19p2

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To be removed:

cpc (with macro/cpc) - REMOVED (2021-08-19 962a18d5)
dch - REMOVED (2021-08-17 777f0207)
fsa - REMOVED (2021-08-16 70a2aac5)
ndet - REMOVED (2021-08-16 862f2037)
sft - REMOVED (2021-08-16 - 5d6970ca)
strawECT - REMOVED (2021-08-16 - 139b45a3)
strawendcap - too deep linked to lhetrack/MpdEctTrack* (inside InitGeo)
tgem - REMOVED (2021-08-16 - ffc19584)
stt - REMOVED (2021-08-19 1f7df230)

TODO: Detectors that are tied somewhere else, investigate the ties and document them, discuss with A. Zinchenko

Issues / Questions: After removing TGEM and DCH, inside MpdEctTrackFinderTpc.cxx there is no KalmanHits generator inside the function MakeKalmanHits. Strawendcap requires MpdEctTrac* to be removed - this must stay, solution to be discussed with zinchenko

Can lhetrack/MpdSftTrackFinderTpc.* be removed? Since there is part Sft this probably needs to be removed in connection with removal of sft