Feat fetch plot data#52

Warning: the checkbox at the second option: Access-Control-Allow-Headers must be checked IF you use Chrome CORS Plugin, Cors Everywhere worked fine.

What I did: Implemented mechanism in apiSlice to fetch data for the available plot types and cache them in the redux store afterwards.

In this image you can see that the data is fetched for a certain subgroup of all fetched models, AFTER the request for the models has finished.

In order for you to verify the fetching you have to install the ReduxDevTools plugin and then check the actions that are dispatched and the state afterwards. First it should dispatch a loading status in the specific store location, next it should update the data and status if it succeeds.