feat(core): ingress server status endpoint

[bzp2010]

Description

Add the health/ready endpoint for Kubernetes probes.

--listen-status 3001

curl http://127.0.0.1:3001/healthz/ready -i
HTTP/1.1 200 OK
Content-Type: text/html; charset=utf-8
Content-Length: 2
Connection: keep-alive
Keep-Alive: timeout=5

OK

Checklist

• I have explained the need for this PR and the problem it solves
• I have explained the changes or the new features added to this PR
• I have added tests corresponding to this change
• I have updated the documentation to reflect this change
• I have verified that this change is backward compatible