Emit docs for API services

[htuch]

Start with the access log API services.

Migrated from https://github.com/envoyproxy/data-plane-api/issues/351

[htuch]

We should also make use of the resource type annotations in #9566 here.

[ankatare]

@htuch url as mentioned in description is notopening.

this one: https://github.com/envoyproxy/data-plane-api/issues/351

[htuch]

@ankatare not sure why that no longer works, but I think the title captures what we want here. We have a bunch of service definitions in api/envoy. These are not rendered via protodoc today but it would be good to have some output here to describe the gRPC and HTTP services, e.g.

envoy/api/envoy/service/cluster/v3/cds.proto

Line 21 in 77d7cec

// Return list of all clusters this proxy will load balance to.

.

Today, we manually put these descriptions together in https://www.envoyproxy.io/docs/envoy/latest/configuration/overview/xds_api.html?highlight=clusterdiscoveryservice#post--envoy.service.cluster.v3.ClusterDiscoveryService-StreamClusters.

We describe the request/response messages in https://www.envoyproxy.io/docs/envoy/latest/api-v3/service/service, but not what the gRPC and HTTP service methods look like.

Ultimately, I think this bug involves automatically generating what we have today in https://www.envoyproxy.io/docs/envoy/latest/configuration/overview/xds_api.html?highlight=clusterdiscoveryservice#post--envoy.service.cluster.v3.ClusterDiscoveryService-StreamClusters from the service descriptors, and linking them to the relevant request/response messages in https://www.envoyproxy.io/docs/envoy/latest/api-v3/service/service, again, done programatically via protodoc.

CC @phlax for docs visibility.

[ankatare]

@htuch ok. Thanks for detailed explanations. let me check this

[ankatare]

/assign