Change deployment and port configurations

[dchiller]

Currently, debug settings are determined by the port on which the nginx container listens. It would be much clearer if this was decoupled. Also, conversation in #815 suggests that it would be better if nginx listened (behind the edge router) on a non-80 port.

For this issue:

1. Have nginx always listen on a non-80 port.
2. Configure debug with an explicit environment variable (for example, DEVELOPMENT: True or DEVELOPMENT: False
3. Update documentation for the above.