[kolla] Dropping support for vmtp in Yoga

Dear Users of Kolla! The Kolla project, so far, provided vmtp [1] image and ansible role. However, the status of those has been unknown (the ansible role looks pretty stale, still referencing ubuntu 16.04!) and now the vmtp image is failing to build so we are forced to disable it. [2] The project itself [1] looks rather unmaintained and it's outside of the openstack namespace so our plan is to drop support for it entirely in this cycle (Yoga). Please reply to this mail if you are using vmtp with Kolla in some recent release and are willing to contribute to let us keep supporting it. [1] https://opendev.org/x/vmtp [2] https://review.opendev.org/c/openstack/kolla/+/820043 Kind regards, -yoctozepto