add import snippet to terraform-mode (#508)

https://developer.hashicorp.com/terraform/language/import#syntax

Author: guitmz

snippets/terraform-mode/import

@@ -0,0 +1,9 @@
+# -*- mode: snippet -*-
+# name: import
+# key: import
+# --
+
+import {
+  to = "${1:to}"
+  id = "${2:id}"
+}