kubecfg doesn't allow updates because of path checks

Currently, `kubecfg -c <json> update services/<id>` fails because `services/<id>` is checked by ToWireFormat instead of just `services`.  Updates should allow two path segments and check storage on the first.

Check for 1 path segment on create/list, 2 on update/delete, and allow any number of path segments on get (for now).

Also pretty prints the list of actual types that are supported for create/update, which today corresponds to the list of types that are supported period.
This assumes the arg doesn't start with a /, which it might.