Expose karaf commands for showing operation status of the southbound

Expose karaf commands to show the operational state of the plugin. It helps in debugging the southbound plugin. Some of the possible command can be
(1) Show connected device (with flag, controller initiated or switch initiated)
(2) Show bridge created on specific connection
(3) Show details of individual bridge on specific connection
(4) Show output like ovs-vsctl show for specific connection