When sending bulk email check if course is authorized.
Also the idash_mode property is stored seperately for each course.

LMS-2565
Drag and drop on container page.

STUD-1309
dnd container page styling
Switch the container page to use the new view
Restore the ability to drag at any level inside a vertical and clean up templates.
Update unit test based on changes in master.
fix for Studio 404 and 500 page layouts
STUD-864
Only show drag handles in draft mode
Bok choy acceptance test for drag and drop.
Allow for no runtime_type in the context.
Fix Jasmine tests

Also, rewrite them to be easier to comprehend, and to not use magic constants (or to use fewer, at least).
Clean up coverage and code quality issues
Fixed and added more tests for bulk email.

LMS-2565
Test cleanup.
BLD-715: StringResponse i18n.
Address Christina's review comments
Ensure system language is released in dark lang middleware

LMS-2644
Reset the jenkins ruby environment before tests run
Merge pull request #3602 from edx/sarina/LMS-2644

Ensure system language is released in dark lang middleware
Merge pull request #3590 from edx/anton/i18n-string-response

StringResponse i18n.