Clever, Classlink, Other LMSs

Building on #210 and #213 we need to expand the space of other LMSs and integration tools. Clever and Classlink are competitors/supporters of Canvas and Schoology. We need to survey the existing tools and form a plan for adapting to them in or at least a guideline for future additions. This is necessitated by some of our potential collaborators and the need for documentation and a clear path for the others that can be made by new students.

Review issues #210 and #213, then survey Clever, Classlink, Canvas, Schoology, and other LMS integration tools. Document the compatibility findings, a plan or guideline for future additions, and a clear path that new students can follow.

Written by the indexing model from the issue text.