MuonTesterTree - Add common Tree mechanism & store sample meta data

Following changes are introduced

• Move all MuonTesterTree classes to MuonVal namespace
• EventInfoBranch: Toggle whether pile-up information, lhe information, prw information or trigger information is dumped into the TTree in the constructor.
• MuonTPMetaAlg: This algorithm keeps track of the lumi blocks seen by the job and the number of processed events.
• MuEntryVariables: Move the module to a PRDTesterModule
• MuonTesterTree: Add the possibility to link multiple Trees against each other.

Tagging: @goblirsc, @pscholer, @mvozak, @sangelid