Increase largest max width

[andy-armstrong]

This PR makes the largest max width 1920 instead of 1280, to better support wider screens.

See https://github.com/edx/edx-platform/pull/16391 for its usage in edx-platform.

Sandbox: https://andy-armstrong.sandbox.edx.org/courses/course-v1:edX+DemoX+Demo_Course/courseware/interactive_demonstrations/19a30717eff543078a5d94ae9d6c18a5/?child=first

[HarryRein]

It looks like the learner profile is having issues with the new rule for max-width. We probably want to remove that dependency in the profile. Check out the styling on the content-wrapper.

Also, the courseware has a max width that makes this a bit quirky. Will your other story finish that?

[andy-armstrong]

@HarryRein The courseware max width was a deliberate decision to make HTML and CAPA blocks have a max width of 900px. It mostly looks okay, but the example you show is a little odd due to the giant floated image. I think it is a net improvement but we can discuss whether there's anything to do with @marcotuts.

[andy-armstrong]

@HarryRein Let's discuss on the other PR. I'd like to release this one as is if that's okay with you. Can you give me thumbs for just the changes here.