Wordpress_mariadb recipe improvements.

* Unified dumpdb_mysql.sh script.
* Added the restoredb_mysql wrapper script.
* Minimal changes in storage_backup script.

.recipes/wordpress_mariadb/docker-compose.yml

@@ -1,6 +1,5 @@
 # Wordpress with MariaDB
 #
-#version: '3'
 services:
   # https://hub.docker.com/_/wordpress
   # https://github.com/docker-library/docs/tree/master/wordpress