VLANs and Sub-interfaces

Work in progress..

Main points:

VLs can be divided into logically separated sub-VLs (VLANs)
The "trunk" VL and a "sub" VL would be represented with two nodes:
1. Both of the onap.nodes.VL type
2. The relationship between the two nodes is specified using the "division" capability/requirement pair, capability type onap.capabilities.VL.Division
No need to introduce to the model the concept of a sub-CP. Linking a CP to a "sub" VL node is what makes the CP a "sub" CP

node_templates:
  vl_1:
    type: VL
    
  sub_vl_1:
    type: VL
    requirements:
      - division:
          node: vl_1
          capability: division
          
  sub_vl_2:
    type: VL
    requirements:
      - division:
          node: vl_1
          capability: division


  cp_1:
    type: CP
    requirements:
      - link:
          node: sub_vl_1
          capability: link
      - bind: 
        # bound to some node
          
  cp_2:
    type: CP
    requirements:
      - link:
          node: sub_vl_1
          capability: link
      - bind: 
        # bound to some node