PLAT-1408: Import csrf from new path.

cms/djangoapps/contentstore/views/public.py

common/djangoapps/student/views.py

lms/djangoapps/courseware/module_render.py

lms/djangoapps/courseware/views/index.py

lms/djangoapps/courseware/views/views.py

lms/djangoapps/discussion/views.py

openedx/features/course_bookmarks/views/course_bookmarks.py

openedx/features/course_experience/views/course_home.py

openedx/features/course_experience/views/course_outline.py

openedx/features/course_experience/views/course_updates.py

openedx/features/course_search/views/course_search.py