Replace docker group with container-engine

This is part of the move to support podman in kayobe.

Change-Id: I9899ca0542b81d6e3752c464bdebfb14cbf0ed48

Author: jovial

etc/kayobe/inventory/groups

@@ -65,15 +65,20 @@ vgpu
 ###############################################################################
 # Service groups.
 
-[docker:children]
-# Hosts in this group will have Docker installed.
+[container-engine:children]
+# Hosts in this group will have Docker/Podman installed.
 seed
 controllers
 network
 monitoring
 storage
 compute
 
+# NOTE(wszumski): Remove once https://review.opendev.org/c/openstack/kayobe/+/909686 has
+# merged. Added to get the group rename to pass CI.
+[docker:children]
+container-engine
+
 [docker-registry:children]
 # Hosts in this group will have a Docker Registry deployed. This group should
 # generally contain only a single host, to avoid deploying multiple independent