Separate instances per conference

Our fork of the frab codebase has evolved last year from the Budapest conference to the Malmö conference. This lead to changes in the models as well as in the views. The general application logic, the controllers, has mostly not been touched.

The changes in code lead to errors in the presentation of the Budapest conference. Additional regressions for both Budapest and Malmö can be expected with the integration of further requirements and changes for upcoming conferences, like Manchester and alike.

Following up from this high level perspective, we can already conclude to:

• Redeploy current scriptum.degrowth.net to malmo.degrowth.net
  • delete other conferences on malmo.degrowth.net
  • test email delivery, e.g. password reset
• Redeploy current scriptum.degrowth.net to budapest.degrowth.net
  • delete other conferences
  • Bonus: ideally rollback the codebase to a post-conference state
  • test email delivery, e.g. password reset
• Provide a simple landing page on scriptum.degrowth.net to explain the situation
• Redirect the conference's respective namespaces to their new subdomains to preserve old links
• Deploy manchester.degrowth.net as an empty conferenc from the adapted state of the application that solves #199 (closed), and create a conference example

The subdomains and their naming scheme (*.scriptum.degrowth.net, *.scriptorium.degrowth.net, conference?) can be debated.