Bug 5061: Integrate BGPPeerModule with blueprint

Bug 5061: Integrate BGPPeerModule with blueprint

Instead of creating a new BGPPeer instance via CSS module,
transform peer configuration to OpenConfig Neighbor DTO
and write to config DS. BGP deployer will take care of the instance creation.
Add more mapping utility funtions to OpenConfig mapping service.
Also we want to register peer instance as a runtime MX bean to collect statistics,
hence register Peer as a OSGi service and retreive it when module's createInstance
is invoked to register bean there.

Change-Id: Ic5b1ed556f3af000a96cde94aaa669fed2b64f74
Signed-off-by: Milos Fabian <milfabia@cisco.com>
(cherry picked from commit 912da09d223db30bc7db7e10b92f474ed82b87ea)