un-vendor everything

Signed-off-by: Eric Malm <emalm@pivotallabs.com>
bundle update; bump cf-message-bus and nats

This adds cluster support to cf-registrar.

Signed-off-by: Eric Malm <emalm@pivotallabs.com>
update registrar to support clustered nats config

also mbus => message_bus_servers everywhere for consistency

[#60443956]

Signed-off-by: Eric Malm <emalm@pivotallabs.com>