No more Ruby dependency and most important more than 10 times less build time (at least on Windows)!

* Prep for v4.3.0

* More updates for v4.3.0.

* rerun to build docs source map

- Move 4.1 docs to 4.2
- Update versions everywhere to 4.1.3 with release script
- Manually bump the shorthand version in package.json
- Add 4.2 to the versions docs page
- Update some redirects
- Fix tests asset URLs
- Bump Nuget and more

Reduces duplication and makes maintenance easier.

(again)

https://github.com/twbs/bootlint/wiki/W007

With the current docs directory setup, I'm making too many mistakes and have to manually address path changes and directory moves on deploy. This makes for a frustrating experience developing locally and shipping releases. With this PR, we're basically back to the same setup from v3—duplicating the dist directory into our docs directory. Not the most ideal, but very straightforward for me as the release manager.

* update docs path from docs/4.0/ to docs/4.1/

* bump version to 4.1.0

* Update redirects to work for 4.1 docs move

* Update docs version switcher to include latest and link to 4.0 docs

* re-run dist

* Update package-lock.json

* Update docs-navbar.html

* Update Dashboard example

- Replaces .sticky-top on .navbar with .fixed-top
- Adjusts padding on main content area and sidebar to account for fixed navbar
- Move to padding in sidebar instead of top: 48px; fixes Firefox rendering issue
- Adds new .shadow utility for a little extra cherry on top
- Moves sticky styles to separate feature query ruleset to avoid IE rendering issues

* Add .w-100 to chart to fix IE horizontal scroll from label that extended past viewport

* fix cover nav

* Improve signin visuals and alignment with that flexbox love

* rewrite cover example in flexbox

* lighten signin bg

* first pass at pricing example

* redo examples index with data file

* tighten up spacing a bit

* update navbar descriptions

* link pricing

* move that back

* property order

* Fix test errors.

* Compress pricing.png.

* add form validation example

* remove that

* rename that

* restyle and space out

* fix errors

* change order

* cleanup album css and styles

* tweak examples index

* make it a badge

* options

* improve sticky footer alignment

* redesign example index

* brand new blog layout

* start new screenshots

* new product example page a la apple

* add email field

* fix linter, remove unused blog css

* hook up feather icons to start

* redo dashboard

* fix linting

* add floating labels example

* formatting

* formatting

* lint

* fix values o...

Having it uppercase doesn't offer anything and the lowercase version slightly improves gzip compression.

Structure examples with appropriate `<main>`, `<header>`, `<footer>`

fix location of favicons so it loads when viewing the examples. This is the only one I found in the project, so I am assuming it is the right one to point to (#22895)