Allow self hosted installs to lockdown some settings

[mlhess]

Description

This pull requests makes many changes to the overall structure of controllers and views. It will remove some options from controllers and hide text in views.

Testing instructions

In 1.py add

settings.academy_mode = False
settings.lti_only = False

Validate that you can't see facebook/twitter/etc (outside of the book) Validate you can't create a user account, or add a course (auth via lti to test this) Validate the scheduler does not start. Validate the privacy policy is gone

[presnick]

Merged this to my new coursera branch.