Added draft for mariadb docker role

roles/docker-mariadb/tasks/main.yml

@@ -0,0 +1,23 @@
+- name: Create Docker network for MariaDB
+  docker_network:
+    name: mariadb_network
+    state: present
+  when: run_once_backup_docker_to_local is not defined
+
+- name: install MariaDB
+  docker_container:
+    name: mariadb
+    image: mariadb:latest
+    detach: yes
+    env:
+      MARIADB_ROOT_PASSWORD: "{{central_mariadb_root_password}}"
+    networks:
+      - name: mariadb_network
+    published_ports:
+      - "127.0.0.1:3306:3306"
+  when: run_once_backup_docker_to_local is not defined
+
+- name: run the docker_mariadb tasks once
+  set_fact:
+    run_once_backup_docker_to_local: true
+  when: run_once_backup_docker_to_local is not defined