service: Add support for service postgres containers

roles/service/meta/argument_specs.yaml

@@ -67,6 +67,23 @@ argument_specs:
         required: false
         default: {}
 
+      service_database_type:
+        description: >
+          Database type to set up. It will be run in a docker container accessible to the service at host <service name>-{{ service_database_type }} on the
+          default port. The database user will be {{ service_name }} and password will be available as the _service_database_password variable.
+        type: str
+        required: false
+        choices:
+          - postgres
+          - none
+        default: none
+      service_postgres_tag:
+        description: >
+          Postgresql version to use. Can be debian (n) or alpine-based (n-alpine), where n can be major version like 14 or minor like 14.13.
+          Required if service_database_type is postgres.
+        type: str
+        required: false
+
       service_additional_containers:
         description:
           - List of additional containers for the sercice.