Deprecate PostgreSQL support

Since PostgreSQL support was removed from neutron, we are no longer
able to deploy OpenStack with PostgreSQL as its database backend.

Change-Id: I3e179373320f0d7f8d0744fec95c253daf8ac868
Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>

manifests/db/postgresql.pp

@@ -1,5 +1,6 @@
 # == Definition: openstacklib::db::postgresql
 #
+# DPERECATED !!
 # This resource configures a postgresql database for an OpenStack service
 #
 # == Parameters:
@@ -39,6 +40,9 @@ define openstacklib::db::postgresql (
   # DEPRECATED PARAMETERS
   Optional[String[1]] $password_hash               = undef,
 ) {
+  warning("Support for PostgreSQL has been deprecated and will be removed in \
+a future release")
+
   if $password_hash != undef {
     warning('The password_hash parameter was deprecated and will be removed
 in a future release. Use password instead')

releasenotes/notes/deprecate-postgresql-a626f49f46bd6799.yaml

@@ -0,0 +1,5 @@
+---
+deprecations:
+  - |
+    Support for PostgreSQL has been deprecated and will be removed in a future
+    release.