MixingModule configurations cleaning, removal of CrossingFrames

CrossingFrames switched off in DIGI, ON only in VALIDATION 
mixObjects and digitizers defined as PSet in separate files
remove all the FIX and AVE configurations, replace them with common templates, exact definition just in
StandardSequences (Mixing.py)

Ready to move TrackingParticles only in VALIDATION, needs reconfiguration of validation sequences to be accomplished