move helper script to scripts dir and add one to Makefile

scripts/template/test/test_service.py.j2

@@ -0,0 +1,11 @@
+from __future__ import unicode_literals
+
+import boto3
+import sure  # noqa
+from moto import mock_{{ service }}
+
+
+@mock_{{ service }}
+def test_list():
+    # do test
+    pass