[Protobuf][2/n] Expand protoc-gen-yarpc-go to emit ActorUUID accessor for actor_uuid annotated fields

[mark200]

Description

• Plugin protoc-gen-yarpc-go is extended with uber.auth.annotations.actor_uuid annotation and emits a uniform ActorUUID accessor for every type that carries (via a method's args) an annotated field.
  For example, the following proto file

  message GetUserRequest {
    string requester_id = 1 [(uber.auth.annotations.actor_uuid) = true];
    string target_id = 2;
  }
  
  service UserService {
    rpc GetUser(GetUserRequest) returns (GetUserResponse);
  }

  generates the following method inside [proto_file].pb.yarpc.go

  func (t *GetUserRequest) ActorUUID() []string {
     return []string{t.GetRequesterId()}
  }

  Additionally, the following scenarios are accepted:

  • Cycles, nested requests, multiple annotations, repeated fields, map fields (look at withuuid.proto for reference)

Stacked PRs

1. internal/protogen — shared descriptor-agnostic core PR#2535
2. this PR — gogo converter + ActorUUID() emission in protoc-gen-yarpc-go PR#2519
3. server-side validator wiring PR#2520

Test Plan

1. Unit tested (here, inside yarpc-go)
2. Changes pulled into monorepo - PR#214339
3. E2E test - PR#214339

RELEASE NOTES:
Added support for protobuf annotation uber.auth.annotations.actor_uuid