Switch Epoch structure from 4-3-3 to 3-3-4

[lehins]

This is important for Genesis work. Ideally it should be done before Conway, however if it can be implemented in isolation within a single rule, then an intra-era hardfork could be possible as well.

Timeline for this is sometime next year (unclear when exactly).

Any questions about this should be directed to Christian Badertscher and Duncan

[nfrisby]

Clarification: Esgen noticed my mistake. The correction is: since the Babbage protocol is defined in ouroboros-consensus, this is actually a change for the Consensus Team to make.

I'm therefore going to Transfer this Issue to ouroboros-consensus.

Sorry for the noise! (I've also clarified this with Christian, for FYI.)

[nfrisby]

Also: Christian asked us to consider 4-2-4 which he said he would generally prefer of 3-3-4, if we don't have a significant preference.