Move redirection/enrollment to AccessView and trigger it using an event.

Ensure window.isExternal is loaded

Don't set a default for terms of service

For paid courses, add the course to the cart and redirect to the shopping cart view.

Don't send form method and url as form data.

Stub window.analytics in the access view test.
Merge pull request #5883 from edx/will/logistration-enrollment-cleanup

Logistration: enrollment cleanup and a few fixes