BSv5.2 upgrade followup

[chalin]

This is a followup meta issue to #470.

• Fix link text and hover color contrast for all bgs #1525
  • Link hover color contrast is insufficient when block bg is dark #1482
  • Link text and hover color contrast in footer is insufficient #1483
    • [BSv5] Footer link icons: use text color #1547
• No more og:site_name when building under Hugo 0.112.x #1531
• Allow link-color to be set by projects #1631
• Ensure that the swagger-ui shortcode still works and that rendered pages are properly formatted.
  Might be good to address the following at the same time: swagger-ui DOM XSS #1076
• Reactivate code-block copy feature #1267
• [BSv5] Drop bg-gradient-variant() mixin #1369
• Drop / inline prepend() SCSS function #1385
• Use Hugo render hook instead of AnchorJS #1460
• [UG] Refer to Bootstrap 5 doc pages and files #1844
• Drop jQuery #1436
• Reintroduce RTL support using BSv5 RTLCSS #1442

Other un-triaged post-upgrade checks and suggested changes:

• Table style override still necessary? For details, see Apply styling to all elements in td-content #1255 (comment)
• Simplify how code color is defined #1387
• Adding shortcode for accordion component (Bootstrap 5) #1391
• Consider using Bootstrap pagination support #1423

Related:

• Upgrade to Bootstrap 5.3 #1528
  • Upgrade to Bootstrap 5.3.3 #1563

[chalin]

FYI, BSv5.3 is now officially out! https://github.com/twbs/bootstrap/releases/tag/v5.3.0