Add metadata to disable apache mods

Introduce a new pillar apache:server:mods that is a dictionary with
the new module metadata. Allows to manage apache modules by setting:

enabled: True/False
status: disabled/enabled

Change-Id: I01c4a6d0f77ec22d7dd33c047f8e349216e8db67
Related-Prod: PROD-23524
diff --git a/defaults/openstack/init.yml b/defaults/openstack/init.yml
index cc580b8..e6dd320 100644
--- a/defaults/openstack/init.yml
+++ b/defaults/openstack/init.yml
@@ -36,3 +36,6 @@
     # Openstack memcached server protocols
     openstack_memcached_proto_tcp_enabled: True
     openstack_memcached_proto_udp_enabled: False
+    # Apache mods defaults
+    apache_mods_status_enabled: True
+    apache_mods_status_status: 'disabled'