Add placeholder product for fill scheme and use in Ecal Local Reco

Add placeholder FillSchemeInfo product which contains only the bunch spacing for now, but should contain the full filling scheme in the future.

Dummy producer added which fills bunch spacing from PileupSummaryInfo for MC and from hardcoded run list for data.   (n. b. the bunchSpacing parameter in the default mixing nopileup config was changed to be easily distinguishable from 50ns and 25ns, but this should have no physics effect)

Ecal local reco modified to use the FillSchemeInfo (but only switching between 10pulse config for 25ns and 5pulse config for 50ns for now)

@bachtis @emanueledimarco @argiro @lgray

If this is a brand new class that has never been stored before than 2 is best. You tend to see 10 because we must make sure that IF the object had  ever been stored without a version number, which was true in the beginning of CMSSW, then the version number you start with must be greater than the maximum number of pre-version number schemas of that class which had ever been to written. Given figuring that out would be crazy hard, we guessed that 10 was larger than the max number of schema changes for any one object we had ever written.