Changes to make Pixel CPE thread safe

Main purpose of this is to make Pixel CPE thread safe.
The following changes were implemented:
- Remove all mutables from Pixel CPE
- Move Si*TempateStore vectors our of Si*Tempate, in order to store Si*TempateStore vectors as non-mutables in *CPE, while keeping the changes to Si*Template minimal
- Remove ClusterParameterEstimator template and force to return pixel QualityWord directy
- Introduce RecoLocalTracker SiPixelRecHits SiPixelGenError, for faster LAwidth computation in CPEGeneric.

It has been merged with the request 3236 which contains all the changes by Pal, required for this request.

Passed tests runTheMatrix.py --useInput=all --list=limited
No regression expected, No regression observed