Deprecate API v2 (#7761)

* deprecate api-v2

* remove v2 test helpers

* remove unused string

website/server/middlewares/domain.js

@@ -0,0 +1,13 @@
+import domainMiddleware from 'domain-middleware';
+
+module.exports = function implementDomainMiddleware (server, mongoose) {
+  return domainMiddleware({
+    server: {
+      close () {
+        server.close();
+        mongoose.connection.close();
+      },
+    },
+    killTimeout: 10000,
+  });
+};