Use theory 400 for the fit bot

Created by: scarlehoff

Since pineappl will soon become the default and main provider for fktable, the fit bot should be testing with theory 400.

We might need to create a theory specific for this since theory 400 has a very large number of points and I don't have a feeling of how much memory it will take.

It might also be a good idea to retain a "fitbot-legacy" in order to check that a fit with theory 200 also works.