(WIP) WL-98 As a course instructor, auto-register (as well as auto enroll) a list of students into my course

@chrisndodge here are the changes related to WL-98 for your quick reivew. 
we have written the test cases but only one coverage is missing in our code.  
currently we did not check/test the code for quality.

In order to test this feature you need to set the flag: 
FEATURES['ALLOW_AUTOMATED_SIGNEDUPS'] = True
This class name seems very much tied to the backend processing and I'm assuming that this is where we're placing end user confirmation and error messages. If that's the case, I'd prefer we use UI-focused known class names like ```.message```, ```.message-error```, or ```.message-confirmation```.