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

spec/MongoTransform.spec.js

@@ -24,7 +24,7 @@ describe('parseObjectToMongoObjectForCreate', () => {
     done();
   });
 
-  it('built-in timestamps', (done) => {
+  it('built-in timestamps with date', (done) => {
     const input = {
       createdAt: "2015-10-06T21:24:50.332Z",
       updatedAt: "2015-10-06T21:24:50.332Z"