Unofficial regen identity 'if-OTUCn-ODUCn-regen' support for Open ROADM 7.1 YANG models

Some non-compliant Open ROADM devices propose an additional regen identity 'if-OTUCn-ODUCn-regen' in the common Open ROADM YANG model org-openroadm-port-types.

Though this identity should have been advertised through a deviation, this does not raise any compatibility problem with compliant devices.

For supporting regenerator mode on 7.1 models, it has been agreed that there will be a model change, but there will not be any new OpenROADM MSA 7 release, as this is a small change.

For a maximum portabilitly a modified version of the model will be proposed in TransportPCE to integrate this unofficial regen identity.

Common/org-openroadm-port-types@2020-03-27.yang

identity if-OTUCn-ODUCn-regen {
      base supported-if-capability;
  }

This is ideally a temporary work-around proposes  until a compliant solution is found.
The right way to support this would be to create a new model with the desired deviation and to overload the device capabilities with it at mount time.