Renamed the mariadb, openldap and postgres database

roles/svc-db-postgres/config/main.yml

@@ -0,0 +1,11 @@
+hostname: "svc-db-postgres"
+network:  "svc-db-postgres"
+port:     5432
+docker:
+  images:
+    # Postgis is necessary for mobilizon
+    postgres: postgis/postgis
+  versions:  
+    # Please set an version in your inventory file! 
+    # Rolling release isn't recommended
+    postgres: "latest"