Populate OTN link in topology

OTN services are created sequentially. This implies needed supporting services are present and supporting links have been populated in the topology to allow path calculation. Thus we need to populate OTN link in topology after OTN service has been succesfully provisionned. This stories includes the creation of all methods required in both OTN Renderer as well as Topology management. Link discovery based on accepted SAPI and DAPI on the interfaces has been put temporarly aside because SAPI and DAPI are optional parameters that may or may not be in the device models depending on the vendors.

Evaluation indicators:

• code published on master branch , not necessarily merged