Automatically provide "expand all" and "collapse all" for accordions

[CharlesBelov]

Prerequisites

• [X] I have searched for duplicate or closed feature requests
• [X] I have read the contributing guidelines

Proposal

Provide Bootstrap accordions "expand all" and "collapse all" links immediately before the first accordion on a page without the page editor having to code these.

• Site option to automatically apply to all pages having accordions
• If site is not set to apply to all pages, provide a way to set by page
• If there are multiple accordions on a webpage, the links would appear immediately before the first accordion and apply to all accordions on that page.

Motivation and context

Benefit:

• People for whom accordions present a challenge can choose to view all content at once instead of being forced to deal with the accordion.

Such people might include:

• People for whom it causes pain to do a lot of clicking
• People who need to be able to see content from multiple sections at once
• People who locate content of interest on a page by using the browser's find text on page feature (Ctrl-F or Cmd-F, may vary by browser)
• People whose concentration is disrupted by having to do a lot of clicking
• People who want to print the entire page content

[CharlesBelov]

See also Accordions on Desktop: When and How to Use by Huei-Hsin Wang of Neilson Norman Group, which gives guidelines for accordion use.