Uses orphans/widows trick from @fran-worley at https://github.com/twbs/bootstrap/issues/20925#issuecomment-333492739.

Fixes #20925.

Removes the .justify-content-between from a navbar form example given it's the default style. Instead, mention how to adjust this and link to flex utils.

Closes #25829, closes #25924

This reverts commit 70520855.

While the old one will keep working, better switch to the new one.

This reduces duplication and the chances to forget to update something.

Kept back karma-qunit and qunitjs because tests fail.

* Making use of `prefers-reduced-motion` media query

As discussed in #25249 - if a user (Who is using Safari / iOS) requests
reduced motion in their system settings, we should avoid transitions.

* Ignoring prefers reduced motion for CSS Linting
* Updating copy clarifying the reduce motion functionality in accessibility.md

* Update issue template to break down by bug and template, add support doc to close #23133

* add links from readme for bug and feature templates

it's ≠ its

Add the column/grid to the example code (which is what makes it vertical in the first place)

Rely on `site.url` which is different for production. In that case do nothing with the search result, otherwise when in development remove our url from it.

Previously a search redirected to `https://getbootstrap.com/...`