Contains 2 changes to the GetEnvoyBootstrapParams response to support
consul-dataplane.
Exposing node_name and node_id:
consul-dataplane will support providing either the node_id or node_name in its
configuration. Unfortunately, supporting both in the xDS meta adds a fair amount
of complexity (partly because most tables are currently indexed on node_name)
so for now we're going to return them both from the bootstrap params endpoint,
allowing consul-dataplane to exchange a node_id for a node_name (which it will
supply in the xDS meta).
Properly setting service for gateways:
To avoid the need to special case gateways in consul-dataplane, service will now
either be the destination service name for connect proxies, or the gateway
service name. This means it can be used as-is in Envoy configuration (i.e. as a
cluster name or in metric tags).
Previously, public referred to gRPC services that are both exposed on
the dedicated gRPC port and have their definitions in the proto-public
directory (so were considered usable by 3rd parties). Whereas private
referred to services on the multiplexed server port that are only usable
by agents and other servers.
Now, we're splitting these definitions, such that external/internal
refers to the port and public/private refers to whether they can be used
by 3rd parties.
This is necessary because the peering replication API needs to be
exposed on the dedicated port, but is not (yet) suitable for use by 3rd
parties.
