Co-Authored-By: Shohei Yoshida <fellows3@gmail.com>

Co-Authored-By: Shohei Yoshida <fellows3@gmail.com>

* Remove unused classes/styles and use utilities instead of specific styles
* Use `getElementById` instead of `querySelector`

- Add same advice about keyboard/AT handling to popovers as a callout; also add information about not adding excessive content or interactive controls (and the suggestion to opt for a modal)
- Tweak the tooltips callout for consistency

Notably:

* bundlesize 0.15.3 → ^0.17.2
* eslint-plugin-unicorn ^8.0.2 → ^9.0.0
* terser ^3.17.0 → ^4.0.0

* Prevent .sr-only-focusable overriding properties when being focused

* Typo

I think it makes more sense to link to the Bootstrap package on Yarn here (like the package link for NPM above)

* Move close icon to components

* Remove redundant float from close

Replace snippets and examples in dropdown docs to use semantic `ul` and `li` elements.

It results in bigger files.

Previously deprecated in v4.x, this clears out the now unused Sass option and removes some unused mixins. Arguably we could remove more, but I like the hover-focus mixin and we make extensive use of it across the project.

* Documentation tweaks

* Remove redundant col-12 classes

30 Categories , 2100+ SVG and icons from icofont

* Migration docs page for v5

* Add JS section, tweak some copy

* Update migration.md