This is the main patch for the migration of the stable/21.10
charm to charmhub for the stable/train branch (train track on
charmhub). This patch initially supports bionic from queens
to train, and does not support ussuri. It supports upgrades
from bionic-queens to bionic-train (with each intermediate
step needed). Crucially it does NOT set a default
openstack-origin, which means installing train/stable
without specifying the openstack-origin will result in a
bionic-queens installation. This is intentional as the branch
covers queens to train.
* use stable/21.10 libraries
* use zaza/zaza-openstack-tests at stable/21.10
* build.lock files for reactive charms
* bundles refer to ~openstack-charms candidate channel
