Cleanup and modernization of Muon code

part of set of MR !3520 (merged) Rec!2855 (merged) Alignment!260 (merged) Detector!177 (merged)

added cleanup new feature labels

added RTA label

changed the description

mentioned in merge request Rec!2855 (merged)

mentioned in merge request Alignment!260 (merged)

/ci-test Rec!2855 (merged) Alignment!260 (merged)

added ci-test-triggered label

• [2022-04-19 17:25] Validation started with lhcb-master-mr#4256
• [2022-04-19 21:51] Validation started with lhcb-master-mr#4257
• [2022-04-20 15:33] Validation started with lhcb-master-mr#4265
• [2022-04-21 18:23] Validation started with lhcb-master-mr#4273

mentioned in merge request Detector!177 (merged)

changed the description

/ci-test Rec!2855 (merged) Alignment!260 (merged) Detector!177 (merged)

added hlt2-throughput-increased label

/ci-test Rec!2855 (merged) Alignment!260 (merged) Detector!177 (merged)

/ci-test Rec!2855 (merged) Alignment!260 (merged) Detector!177 (merged)

removed hlt2-throughput-increased label

resolved all threads

/ci-test Rec!2855 (merged) Alignment!260 (merged) Detector!177 (merged)

removed new feature label

added Muon label

assigned to @rmatev