Even faster tests (#4868)

* Various improvements in test name / de-duplications

* Reverts to class by class deletion, introduced fast mode that just delete data for mongo

- Speeds up are incredible Executed 1695 of 1713 specs INCOMPLETE (18 PENDING) in 4 mins 19 secs.

* Adds documentation about the deleteEverything

src/TestUtils.js

@@ -1,14 +1,17 @@
 import AppCache from './cache';
 
-//Used by tests
-export function destroyAllDataPermanently() {
+/**
+ * Destroys all data in the database
+ * @param {boolean} fast set to true if it's ok to just drop objects and not indexes.
+ */
+export function destroyAllDataPermanently(fast) {
   if (!process.env.TESTING) {
     throw 'Only supported in test environment';
   }
   return Promise.all(Object.keys(AppCache.cache).map(appId => {
     const app = AppCache.get(appId);
     if (app.databaseController) {
-      return app.databaseController.deleteEverything();
+      return app.databaseController.deleteEverything(fast);
     } else {
       return Promise.resolve();
     }