Add MuonRadiationFilter2 plugin

This module is used to study the FSR filter, before possibly deploying
it in the official CMSSW TauAnalysis/MCEmbeddingTools code.
Add NTupleProducer (EDAnalyzer) for mu+mu events

These can be either di-muon events used as input for the embedding procedure,
or muon embedded samples where muons are replaced by muons.