r/wal-g-pg: Schedule daily backups

WAL archives are not much good without a base backup onto which they
can be applied.  Thus, we need to schedule WAL-G to create and upload a
backup periodically.

roles/wal-g-pg/handlers/main.yml

@@ -1,3 +1,8 @@
 - name: load wal-g-postgresql selinux module
   command:
     semodule -i /usr/local/share/selinux/wal-g-postgresql.cil
+
+- name:  restart wal-g backup timer
+  systemd:
+    name: wal-g-backup.timer
+    state: restarted