Use http in development as a default

- Provides a constant in development settings to set that we are in development
- Adds `DEVELOPMENT` to `settings.development`
- Allows us to switch in `do_dashboard_migration.py`
1. LGTM ¯\_(ツ)_/¯ 
2. Yes, but I prefer the explicitness this gives, which is also my answer to 1.