Add HFRingSum and HFBitCount dataformats and skeleton algorithms

@mulhearn @jimbrooke 
I have added 2 new data formats for using the unused channels: HFRingSum and HFBitCount. Since the algorithms which will use these dataformats are so different (centrality, Tau, flow) I just kept the similar name as the legacy format that it needs to be converted to. 

There is an enum type specified for each of the two dataformats. This could be used to decide (1) which scale is the proper physical scale to be called in PhysicalEtAdder and (2) what should the proper conversion to the legacy format be. The legacy formats are just objects with 4x3bits, so there are several ways to pack physics objects into them.

The goal was to leave the new dataformats as flexible as possible so that the future PP use of them would not be limited. The plan for HI is to use HFBitCounts for the centrality trigger and HFRingSums for the v2 trigger. In both of those cases a single 12 bit value is sufficient to convey the information. 

Please let me know if you have suggestions or complaints about the names or approach.

This branch has been build-and-run tested with both the HI and PP from-RAW configs.