## Proposed Changes
This PR adds more logging prior to genesis, particularly on networks that start with execution enabled.
There are new checks using `eth_getBlockByHash/Number` to verify that the genesis state's `latest_execution_payload_header` matches the execution node's genesis block.
The first commit also runs the merge-readiness/Capella-readiness checks prior to genesis. This has two effects:
- Give more information on the execution node's status and its readiness for genesis.
- Prevent the `el_offline` status from being set on `/eth/v1/node/syncing`, which previously caused the VC to complain loudly.
I would like to include this for the Holesky reboot. It would have caught the misconfig that doomed the first Holesky.
## Additional Info
- Geth doesn't serve payload bodies prior to genesis, which is why we use the legacy methods. I haven't checked with other ELs yet.
- Currently this is logging errors with _Capella_ genesis states generated by `ethereum-genesis-generator` because the `withdrawals_root` is not set correctly (it is 0x0). This is not a blocker for Holesky, as it starts from Bellatrix (Pari is investigating).
## Issue Addressed
Solves #4442
## Proposed Changes
EL clients log errors if we don't query this endpoint, but they are making releases that remove this error logging. After those are out we can stop calling it, after which point EL teams will remove the endpoint entirely.
Refer https://hackmd.io/@n0ble/deprecate-exchgTC
## Issue Addressed
NA
## Proposed Changes
Start issuing merge-readiness logs 2 weeks before the Bellatrix fork epoch. Additionally, if the Bellatrix epoch is specified and the use has configured an EL, always log merge readiness logs, this should benefit pro-active users.
### Lookahead Reasoning
- Bellatrix fork is:
- epoch 144896
- slot 4636672
- Unix timestamp: `1606824023 + (4636672 * 12) = 1662464087`
- GMT: Tue Sep 06 2022 11:34:47 GMT+0000
- Warning start time is:
- Unix timestamp: `1662464087 - 604800 * 2 = 1661254487`
- GMT: Tue Aug 23 2022 11:34:47 GMT+0000
The [current expectation](https://discord.com/channels/595666850260713488/745077610685661265/1007445305198911569) is that EL and CL clients will releases out by Aug 22nd at the latest, then an EF announcement will go out on the 23rd. If all goes well, LH will start alerting users about merge-readiness just after the announcement.
## Additional Info
NA
## Issue Addressed
Resolves#3249
## Proposed Changes
Log merge related parameters and EE status in the beacon notifier before the merge.
Co-authored-by: Paul Hauner <paul@paulhauner.com>
