Add CaloDigits v2 and CaloClusters v2
- add a 'v2' CaloDigit which is not a KeyedObject.
- add unit test
- adapt Calo decoding accordingly
- add a 'v2' CaloCluster which is (also) not a KeyedObject.
- add unit test
Note: must be applied in conjunction with Rec!1740 (merged), which updates the cellular automaton clustering to consume v2 digits, and produce v2 clusters, and updates the consumers of Digits