This is only configured in xDS when a service with an L7 protocol is
exported.
They also load any relevant trust bundles for the peered services to
eventually use for L7 SPIFFE validation during mTLS termination.
* Vendor updates for gRPC and xDS server
* xDS server implementation for serving Envoy as a Connect proxy
* Address initial review comments
* consistent envoy package aliases; typos fixed; override TLS and authz for custom listeners
* Moar Typos
* Moar typos
