Split HTTP and TCP/UDP access log format in EnvoyProxy

[aoledk]

Description:

HTTP and TCP/UDP don't have same command operators, REQ and RESP operators only in HTTP is important for observability. If operators only in HTTP is configured for TCP/UDP, - will be placed in related access log operator.

If user wants to deploy HTTP and TCP/UDP listeners under same GatewayClass with mergeGateways enabled, user can't attach EnvoyProxy to Gateway to let different Gateway use their own access log format, then TCP/UDP will have massive - in access log, it's unnecessary overhead and produce useless info to access log.

As a workaround, user can choose to split HTTP and TCP/UDP to different GatewayClass with their own necessary access log format.

Maybe we can consider allow user to configure access log format for HTTP and TCP/UDP separately in EnvoyProxy.

[optional Relevant Links:]

https://gateway.envoyproxy.io/v1.0.2/api/extension_types/#proxyaccesslogsetting https://www.envoyproxy.io/docs/envoy/latest/configuration/observability/access_log/usage#command-operators