PBS: Consider an option to fast-path the status endpoint

[aimxhaisse]

At scale under load, some beacons may wait for the /status call before sending registrations or may simply fallback locally if it takes too much time ; relayers also tend to return errors at tail, this can result in more blocks being unnecessary built locally just because a relayer took more time. Being able to have the PBS status call immediately returns 200 without querying the relayers reduces the time taken in a hot path of beacons, this helps with attestations/block proposals.

I see two downsides:

• logs can be noisy: if all relayers are down, commit-boost PBS will still be called, will try to reach out to relayers, before returning an error back to the beacon, which will fallback locally,
• if a relayer is badly configured, it may take time to realize it, for this commit-boost could actually check them once at startup, without blocking the hot-path.

[aimxhaisse]

Happy to take this one as well, unsure when I'll have time, ping me if you plan to do it so I remove it from my plate :)

[ltitanb]

We do have something like this which is set using this flag

commit-boost-client/config.example.toml

Lines 18 to 20 in 0c12f37

	# Whether to forward `status` calls to relays or skip and return 200
	# OPTIONAL, DEFAULT: true
	relay_check = true

adding a check at startup would add a nice safety check