Use stable/rocky branch of:

* Kolla
* Kolla ansible
* Bifrost
* IPA
* OpenStack services
* Requirements

Also updates Kolla Ansible inventory template.

The seed deploy job has been made non-voting and non-gating, because we
are waiting for bifrost change https://review.openstack.org/#/c/618740
to merge, be released, and for the kolla bifrost image to use the new
package.

Change-Id: Id5e7fdbd196f96e1e75ffc68bc93aab18fa38aa7
Story: 2001864
Task: 27798
Depends-On: I58e4f951d4a3dd89e0784fd82d8a62dbba374f79