Merge branch 'Remove_MA27' into '21.0'

Remove MA27 and clean up private member variables

See merge request atlas/athena!11334

(cherry picked from commit cfffd84a [formerly 974faa2b26cb119cf525a41e2fa7432d0bdd0a8c])

1139d41a Remove MA27 and clean up private member variables
9a68c581 Remove all references to MA27
fce0467e Remove reference to MA27 from iPatFitter
51c40550 Remove final reference to MA27
449fc553 Update CMakeLists file
014fa0a3 Merge remote-tracking branch 'upstream/21.0' into Remove_MA27
a4936b8d Change solver so something more suitable for the alignment like problems
2ee38b8d code cleanup -> NULL to nullptr
df76f86b start removing cout/cerr
7b7a6af6 Remove the remaining cout/cerr calls

Former-commit-id: 228aee8740d2e80495d97b9861945b8d6d374f3d