CatalogDestinationsOnly is a passthrough that would enable dialing
addresses outside of Consul's catalog. However, when this flag is set to
true only _connect_ endpoints for services can be dialed.
This flag is being renamed to signal that non-Connect endpoints can't be
dialed by transparent proxies when the value is set to true.
No config entry needs a Kind field. It is only used to determine the Go type to
target. As we introduce new config entries (like this one) we can remove the kind field
and have the GetKind method return the single supported value.
In this case (similar to proxy-defaults) the Name field is also unnecessary. We always
use the same value. So we can omit the name field entirely.
