undercloud-deploy: add option to disable paunch

Add a new ansible parameter to control if paunch is enabled or not:
undercloud_enable_paunch (undefined by default).

It'll configure the undercloud.conf and tripleoclient will configure the
right Heat parameter to disable Paunch when wanted.

Change-Id: I67c1f61d8422fba1d70f6075bbb116305513acf6

roles/undercloud-deploy/README.md

@@ -97,6 +97,7 @@ https://docs.openstack.org/tripleo-quickstart/latest/accessing-libvirt.html
 - `undercloud_roles_data`: <null> -- A custom t-h-t roles file. Consumed from ``undercloud_templates_path``
   or an alternative location as well.
 - `undercloud_selinux_enabled`: <'true'> -- Enabled for RHEL by default, Disabled for CentOS by default
+- `undercloud_enable_paunch`: <null> -- Enable or disable Paunch to manage containers. Undefined by default.
 - `undercloud_container_cli`: <'podman'> -- Container CLI to use for the Undercloud deployment. Default to 'podman'.
 
 Role Network Variables

roles/undercloud-deploy/templates/undercloud.conf.j2

@@ -224,6 +224,13 @@ undercloud_enable_selinux = {{undercloud_selinux_enabled}}
 # undercloud_enable_selinux = true
 {% endif %}
 
+# Enable or disable Paunch to manage containers. (boolean value)
+{% if undercloud_enable_paunch is defined %}
+undercloud_enable_paunch = {{undercloud_enable_paunch}}
+{% else %}
+# undercloud_enable_paunch = true
+{% endif %}
+
 # Whether to install Tempest in the Undercloud. (boolean value)
 enable_tempest = {{undercloud_enable_tempest}}