extend the AOD content for EXO Long-Lived needs

This is a pull request to test the changes discussed during the "Scouting Parking & Hotline" workshop.
Regarding the possibility to extend the AOD content to include dE/dx information associated to highPt Tracks as well as the Muon segments (DT and CSC) and hits (RPC).
Instead of creating at least 3 new skims for the EXO Long-Lived searches.

This PR is meant to allow @StoyanStoynev and @slava77 to see what are the proposed changes and to study their impact on the reconstruction and disk space
Automatically ported from CMSSW_7_3_X #6532
all access methods should be const