[kolla] openvswitch-netcontrold image removal

Hello Koalas, The openvswitch-netcontrold image is being dropped, that means in Bobcat release Kolla will not build and publish this image. This image is not supported within kolla-ansible, so it’s not tested and it installs netcontrold outside of the regular kolla venv. It has been used in the past by TripleO - but TripleO will not support Bobcat and beyond. If there is anybody interested in maintaining this image - please come forward posting your comment in the patch [1], otherwise it will be dropped. [1]: https://review.opendev.org/c/openstack/kolla/+/891655 Michal