Document and improve Section 508 compliance

Multiple U.S. govt agencies have recently reached out inquiring about section 508 compliance. I've run a few quick tools and there appears to be a few minor things that need to be addressed. This ticket is to document the errors and warnings for 508 compliance, make improvements when necessary, and compile a compliance document.

Microsoft maintains some good examples of what these documents should contain and look like.

https://cloudblogs.microsoft.com/industry-blog/government/2018/09/11/accessibility-conformance-reports/