Allow separate connectors for clients and networks in fabric environment

Enhancement: Restrict a network connector in FUSE ENTMQ to transport connectors with a specified name when using the fabric discovery url.

In an ActiveMQ setup we may want to separate the traffic between the message brokers and external clients from the traffic between the brokers participating in a network of brokers. For example we may have the external transport connector secured and the interbroker connector plain tcp.

To achieve that we would define a profile within fabric that has a broker config with at least two named transport connectors. The corresponding fabric discovery url would specify the broker group, but wouldn't allow to restrict the interbroker connection to only one of the configured transport connectors.

In a future release that could be realiyzed as part orf the url (something like fab:/default/ib) or as a property of the network connector (something like "preferred-transport-name").