Introduce new folder structure

Ghost User
2018-03-29T15:14:23+02:00

Also added a couple of tests ![coverage](https://gitlab.science.ru.nl/thalia/ThaliApp/badges/feature/folder-structuring/coverage.svg)

![Screen_Shot_2018-02-24_at_00.17.30](/uploads/c5e4cbd9b6c571b56852364f330a81a1/Screen_Shot_2018-02-24_at_00.17.30.png)