Make it possible to submit station layouts

This branch is intended to add station layout submission and review to the public database.

The desired workflow is this:
- Students measure their station
- Students use the submission form to submit the station layout
    - They provide: station/measurements/name/email (recaptcha check)
    - They click a link in their email to confirm their email address
- The submitted data is stored in a quarantine
- A mail is sent to the station contact with a link to a page where (s)he can review the submission
- The contact can then approve/dismiss the measurements
- When the submission is approved the data is added to the DetectorHiSPARC for that station
    - When a previous submission exists the start date for the new layout will be set to the submission date (or a 'start date' provided by the students)

To do:
- [ ] views for submission form
- [ ] views for review form
- [ ] models for quarantine
- [ ] improvements to detector hisparc model
- [ ] templates for the views
- [ ] script to show the layout in the browser
- [ ] cleanup cron for submissions not reviewed for x days