Add "profile" to DQMGenericClient

The MultiTrackValidator harvesting configuration `Validation/RecoTrack/python/PostProcessorTracker_cfi.py` defined `profile = cms.vstring(...)` parameter for DQMGenericClient (since ~2009), but as far as I can tell this option has never been supported by DQMGenericClient.

This PR adds the "profile" functionality to DQMGenericClient (it is essentially just `TH2::ProfileX()`), and changes the parameter type to `untracked` (following the `efficiencyProfile`). I also migrated the other configuration I found with a simple `git grep`, and removed empty definitions.

Passes short matrix, the only impact should be that the profiles defined in
```
Validation/RecoTrack/python/PostProcessorTracker_cfi.py
Validation/RecoTrack/python/HLTpostProcessorTracker_cfi.py
```
appear in the workflows using these.

FYI @rovere @cerati @VinInn