Statistics

[kiliankoe]

As wished for by @danielmatusek

Possible options w/ Autoload data:

• number of charges/month
• which canteens are visited
• what meals are eaten (only somewhat possible)

Also add some pretty diagrams, maybe like a burn-down chart for my emeal balance. Somewhat related to #44.

Is there anything we could with historical purchase data @lucasvog? Possibly some recommendations on when to visit a specific canteen? 😁