Add heroku and aws settings and cleanup base settings file

Lots of things all mixed into one, happy to remove parts that you guys don't like.

- Adds `dotenv` so that we can have a `.env` file that sets up environment variables.
- remove `fusionbox-error-logging` since sentry handles this for us.
- add `settings_aws.py` and `settings_heroku.py` for heroku installs.
- refactor settings into `settings_base.py`.  Need help figuring out a solution for this to work on the dev server.
- bump the reporting level for sentry from `INFO` to `WARNING`
- add compressor to installed apps
- add cachebuster to insalled apps
- remove adding cachebuster to the builtin template tags