Proposal: course accessibility scoring

[cidilabs]

Scoring provides an objective data point to compare the accessibility of all courses at an institution. It also allows institutions to define a base score that is considered acceptable.

Possible variables in a course accessibility score:

• Unresolved errors compared to checks made
• Files with alternate formats compared to total number of document files (pdf, docx, pptx)

We currently don't store the number of checks made on a content item. But this should be a simple addition, though.