Add minimal admin app

Just add a homepage and allow the app to be started in the same way as
the read and write apis are.
Add configuration to admin app
Refactor logging and set up for admin app

- Set the Flask app name correctly for each app - see:
  http://flask.pocoo.org/docs/api/#flask.Flask About the first
  parameter
- Use the Flask app name when setting up logging
- Add logging support to admin app