a11y: skip to content link

[rzach]

Insert a "Skip to Content" link at the top of each page on the website. This will allow screen reader users to skip the top menu directly to the beginning of the chapter content. You can see an example on this page: https://opentextbc.ca/studentsuccess/chapter/learning-action-plan/ If you start tabbing, a "Skip to content" link pops up that takes you directly to the beginning of the chapter. Here is more information: WCAG - Bypass Blocks

[rzach]

Reported to BookML: https://github.com/vlmantova/bookml/issues/8