NorthBound APIs for the Bridge Domain configuration Service.

This is the first cut NB-APIs and the enunciate documentation will be generated once the Jenkins Verify is complete
@ https://jenkins.opendaylight.org/controller/job/controller-verify/ws/opendaylight/northbound/networkconfiguration/bridgedomain/target/site/wsdocs/index.html

At a high level, the current version supports the following APIs :

1. Connect : PUT http://localhost:8080/controller/nb/v2/networkconfig/bridgedomain/connect/mgmt1/172.28.30.51/6634
             Response Data : xml : <node type="STUB" id="mgmt1"/>
                             json: {"@type": "STUB","@id": "mgmt1"}
2. Connect : PUT http://localhost:8080/controller/nb/v2/networkconfig/bridgedomain/connect/STUB/mgmt1/172.28.30.51/6634
             Response Data : xml : <node type="STUB" id="mgmt1"/>
                             json: {"@type": "STUB","@id": "mgmt1"}

3. Create Bridge  : POST http://localhost:8080/controller/nb/v2/networkconfig/bridgedomain/bridge/STUB/mgmt1/bridge1
4. Add Port       : POST http://localhost:8080/controller/nb/v2/networkconfig/bridgedomain/port/STUB/mgmt1/bridge1/port1
5. Add Port, Vlan : POST http://localhost:8080/controller/nb/v2/networkconfig/bridgedomain/port/STUB/mgmt1/bridge1/port2/200

Change-Id: Ic55f6bd20859b78a0e004a39388ee358eae5e61a
Signed-off-by: Madhu Venugopal <vmadhu@cisco.com>