* cleanups
* use ForkedTrustedSignedBeaconBlock.ionit where appropriate
* move `is_aggregator` to `spec/`
* use `errReject` in a few more places
* update enr fork id when time is auspicious
* use network broadcast functions
* Return Ignore for aggregate signature validation timeouts
...consistently between aggregates and attestations.
* clean up some more reject/ignore rules
* shorten texts a bit
* errReject->checkedReject, use err helpers throughout
* get rid of quarantine in exitpool as well