Remove flow (#3350)

* Remove flow types from src

* Finish removing Flow

* Clear out flow-typed, some flow mentions in docs, website flow usage, and some other config

jest-setup.js

@@ -1,6 +1,6 @@
 /**
  * @flow
- * eslint-env jest 
+ * eslint-env jest
  */
 
 import React from 'react';