Style improvements (#2475)

* HooksRouter is enabled by default

* Adds middleswares on PromiseRouter, fixes #2410

* Move testing line to helper

* Modernize middlewares.js

* Moves DB uniqueness initialization to DBController, modernize

* Moves testing related code to spec folder

* remove unused _removeHook function

* Adds tests, docs for Analytics and improvements

* nit

* moves back TestUtils

src/Controllers/HooksController.js

@@ -1,6 +1,5 @@
 /** @flow weak */
 
-import * as DatabaseAdapter from "../DatabaseAdapter";
 import * as triggers        from "../triggers";
 import * as Parse           from "parse/node";
 import * as request         from "request";