multicast counters to subinterface, remove physical counters from sub…

…interface (#934)

* add multicast to ip if, remove physical counters from subinterface

* add in deprecated leaves to subif for backwards compat

* trim whitespace

* add if common submodule

* update spec.yml

* use common grouping for if counters

* cleanup

* bump versions

* bump versions

* merge submodule to openconfig-interfaces

* revert oc-if-ip counters

* revert oc-if-ip counters

* add counter container to wifi ap if model

* update wifi version, fix indent