eth/catalyst: implement kintsugi-spec v3

[MariusVanDerWijden]

This PR implements kintsugi-spec v3 (with engine api version v1.0.0-alpha.5)
A rundown of all changes can be found here: https://hackmd.io/@n0ble/kintsugi-spec
It includes a new fork block MergeForkBlock which should be updated before TTD is reached.
This MergeForkBlock is only used for the forkID calculation, nothing else.
This is a block that should happen before the merge to fork non-merge ready nodes off the network.

[rjl493456442]

So essentially the MergeForkBlock is set as usual fork block, but indicates "we are starting the transition right now, but transition will happen in the next a few blocks"?

[holiman]

From the spec

EL client software MUST:
 -   set mixHash value to the value of the random field of ExecutionPayload or PayloadAttributes structures
  -  replace the difficulty value with the mixHash value in the EVM context and change the return value of the DIFFICULTY opcode to the mixHash

I don't see that being done in this PR?

[MariusVanDerWijden]

I don't see that being done in this PR?

Yes, I have a follow-up PR that implements the RANDOM opcode which will also do the changes needed for mixhash

[MariusVanDerWijden]

So essentially the MergeForkBlock is set as usual fork block, but indicates "we are starting the transition right now, but transition will happen in the next a few blocks"?

Yes exactly, it should just help us to kick off unwanted nodes early from, rather than connecting to them and then yeeting them later on

[holiman]

LGTM

[fjl]

This error type is kind of misplaced in package rpc. I'm merging anyway, but please move it in the next iteration.