Prague1 support for non-critical libraries

[calbera]

Tools not fully enabled with Prague1 support but also not used currently:

• t8ntool needs some additional prague1 verification enforced
• blsync (which beacon-kit doesn't even support) needs to introduce ProposerPubkey

API:

• pending block is not fully correct (PoL tx is included but not with the current parent proposer pubkey as it is not made available to geth's miner)

[calbera]

Note: search for TODO(BRIP-4):... in the code to find where to fix.