Updated NEWEPOCH transition

[JaredCorduan]

We will modify the NEWEPOCH transition.

• The MIR sub-transition will be removed.
• A new ENACTMENT transition will be called immediately after the EPOCH transition. This rule will enact governance actions that have previously been ratified.
• The EPOCH transition will no longer call the NEWPP sub-transition (or compute whether quorum is met on the PPUP state).

Note- the checks currently performed in NEWPP will now all be performed in TALLY. It is imperative that ENACTMENT cannot fail, since the consensus layer will make the decision to hard fork in advance of the epoch boundary.

• Remove MIR transition
• Add ENACTMENT transition
• Implement ENACTMENT based on the specs #3284
• Remove NEWPP transition
• Add EPOCH rule and transition