napalm-yang implement openconfig models

[dbarrosop]

As you probably already knows napalm-yang is a framework to translate native configuration from a device to openconfig models and viceversa. Some examples:

• ios native config to interfaces model: https://github.com/napalm-automation/napalm-yang/blob/develop/napalm_yang/mappings/ios/parsers/config/openconfig-interfaces/interfaces.yaml
• interfaces model to native ios: https://github.com/napalm-automation/napalm-yang/blob/develop/napalm_yang/mappings/ios/translators/openconfig-interfaces/interfaces.yaml

There are plenty of models/vendors to implement so if you want to work on any of those just shout :D