CBR-497: Adapt epoch consolidation for OBFT
CBR-497: Adapt epoch consolidation for OBFT

The original epoch consolidation code only worked for Ouroborous
classic epochs which had an epoch boundary block (EBB) between
each epoch. OBFT has epochs just like classic, but does not have
EBBs. This commit modifies the existing epoch consolidation code
so that it works on both classic and OBFT epochs.

input-output-hk/cardano-sl,input-output-hk/pos-haskell-prototype,input-output-hk/cardano-sl,input-output-hk/cardano-sl,input-output-hk/cardano-sl,input-output-hk/pos-haskell-prototype,input-output-hk/pos-haskell-prototype