This is a design-level update to bootstrap.proto, that plumbs in the
remaining top-level config from v1. It will probably have some small
changes made beyond this as we implement.
Notable differences to v1 are:
* Static/dynamic resources are clearly delineated at top-level, clusters no longer belong to the ClusterManager object.
* Stats sinks are a repeated list of opaque configs, similar to filter.
* Some simplifications to object types, e.g. RLS no longer specifies type (do we want to preserve the v1 generality here?).
Also renamed RLDS back to RLS, I'll admit that it didn't make sense to
cram it into the xDS namespace, it's really a very distinct service on
the data plane and shouldn't be bundled with the control plane services.
Since we may want to use a resolver plugin in most places, it doesn't
make sense to have this strong separation between the two in the API.
Also bonus renumbering cleanup in LDS.
This will be useful for Google and other site specific extension of the
resolving of both names and ports. For listeners, ports and bound
addresses can be expressed in a site-specific format. For upstreams,
host names can be resolved using the plugin.