Mattdrayer/api secureapiview fix

@martynjames @dino-cikatic @dsego @ziafazal -- 

I figured out what was going on with the funky DRF UI behavior.  It seems that the recent change of the SecureAPIView class to support filtering was causing issues with view classes that do not have serializers defined.  For some reason this issue was only manifesting when interacting with the API via the web interface.

I resolved the issue by returning SecureAPIView to its original implementation and creating a new SecureListAPIView class for the classes supporting paging/filtering (ie, UsersList)