INFRA-18260: Add extra logging for requests without ACL tokens

[mattclement]

This adds the abilty to enable extra logging when log_acl_info = true. It is intended to log requests that don't contain ACL info, to facilitate safer ACL enablement.

No logs are generated with the flag off / absent, or when there is a token present.

Logs look like this:

{
  "@level": "info",
  "@message": "No ACL token in request",
  "@module": "agent.http",
  "@timestamp": "2024-09-11T12:30:21.105571-04:00",
  "remote_addr": "127.0.0.1:56100",
  "url": "/v1/kv/",
  "user_agent": "curl/8.7.1"
}