Adding the DQM and Validation packages for the Phase 2 OuterTracker

New packages DQM/Phase2OuterTracker and Validation/Phase2OuterTracker are added. They contain plots based on the TrackTrigger validation for TTClusters and TTStubs.

Timing (per event):
DQM/OuterTrackerMonitorCluster  0.028358 s
DQM/OuterTrackerMonitorStub      0.000449 s
Validation/OuterTrackerCluster       0.000977 s
Validation/OuterTrackerStub           0.000122 s
Validation/OuterTrackerMCTruth    0.001192 s

Largest contribution to timing is due to loading of StackedTrackerGeometry.

@deguio could you please take a look?