v2.0.0: Surprisingly convenient software

Our last release included a lot of code generated in a short time. This release includes a lot of code generated in a long time: Work for this version started in early February! Based on user feedback we go where no mensa bot has gone before: Up to date mensa menus, all the time. At least until January, when the digital signage system of the mensa will change, but that's a problem for future us.

Major features:

• Users can now request the current mensa menu with a button
  • Sadly this means that users will now need to tap twice to report a queue length, instead of once
  • But on the upside, users now have three different keyboards to check out!
• Users can also receive automatic push messages about mensa menus
• Users can modify their settings, on a central screen, including whether they want any messages at all
  • This includes weekday and timeslot selection for mensa menu pushmessages, as well as point collection
• Users who have reported a queue length on a day are automatically excluded from further mensa menu updates to minimize spam

Minor features and changes:

• Users can become beta testers, to slowly test large features
• Users can delete their data with /forgetme
• A whole bunch of backend refactoring and rewriting stuff
• Changelogs have become less spammy for new users
• The keyboard now automatically resizes itself, to offer maximum reading space
• Fixed some minor bugs, I'm sure