remove - vars, update docs to generate from data yml files, update mixins, and generate card, button, bg, and color classes from the sass map

Part of an update to align the naming schemes across our components.

- Renames .popover-title to .popover-header
- Renames .popover-content to .popover-body

Refs: #22092

(Fixes #22414) Rename for consistency `$custom-checkbox-radius`, `$custom-checkbox-checked-icon`, `$custom-checkbox-indeterminate-indicator-color`, `$custom-checkbox-indeterminate-icon`, `$custom-radio-radius`, `$custom-radio-checked-icon`, `$custom-select-sm-font-size`, to `$custom-checkbox-border-radius`, `$custom-checkbox-icon-checked`, `$custom-checkbox-indicator-indeterminate-color`, `$custom-checkbox-icon-indeterminate`, `$custom-radio-border-radius`, `$custom-radio-icon-checked`, `$custom-select-font-size-sm` respectively

Rename for consistency `$table-sm-cell-padding`, `$table-bg-accent`, `$table-bg-hover`, `$table-bg-active`, `$table-inverse-bg-accent`, `$table-inverse-bg-hover` to `$table-cell-padding-sm`, `$table-accent-bg`, `$table-hover-bg`, `$table-active-bg`, `$table-inverse-accent-bg`, `$table-inverse-hover-bg`, respectively (#22414)

(#22414) Rename for consistency `$input-bg-disabled`, `$input-bg-focus`, `$input-border-color-focus`, `$input-box-shadow-focus`, `$input-color-focus`, `$input-color-placeholder` to `$input-disabled-bg`, `$input-focus-bg`, `$input-focus-border-color`, `$input-focus-box-shadow`, `$input-focus-color`, `$input-placeholder-color`, respectively

(#22414) Rename for consistency `$custom-control-disabled-indicator-bg`, `$custom-control-disabled-description-color`, `$custom-control-checked-indicator-color`, `$custom-control-checked-indicator-bg`, `$custom-control-checked-indicator-box-shadow`, `$custom-control-focus-indicator-box-shadow`, `$custom-control-active-indicator-color`, `$custom-control-active-indicator-bg`, `$custom-control-active-indicator-box-shadow` to `$custom-control-indicator-disabled-bg`, `$custom-control-description-disabled-color`, `$custom-control-indicator-checked-color`, `$custom-control-indicator-checked-bg`, `$custom-control-indicator-checked-box-shadow`, `$custom-control-indicator-focus-box-shadow`, `$custom-control-indicator-active-color`, `$custom-control-indicator-active-bg`, `$custom-control-indicator-active-box-shadow`, respectively

(#22414) Renamed for consistency `$nav-disabled-link-color`, `$nav-tabs-active-link-color`, `$nav-tabs-active-link-bg`, `$nav-tabs-active-link-border-color`, `$nav-pills-active-link-color`, `$nav-pills-active-link-bg` to `$nav-link-disabled-color`, `$nav-tabs-link-active-color`, `$nav-tabs-link-active-bg`, `$nav-tabs-link-active-border-color`, `$nav-pills-link-active-color`, `$nav-pills-link-active-bg`, respectively

(#22414) Renamed for consistency `$modal-dialog-sm-up-margin-y`, `$modal-content-xs-box-shadow`, `$modal-content-sm-up-box-shadow`, to `$modal-dialog-margin-y-sm-up`, `$modal-content-box-shadow-xs`, `$modal-content-box-shadow-sm-up`, respectively

Rename `$navbar-*-toggler-bg` to `$navbar-*-toggler-icon-bg` since it's placed on .navbar-toggler-icon (#22564)

— Sizing shorthand comes last
— Add height var and put it to use

— Previously we weren't including the border-width on the computed height, leading to alignment issues.

— New system utilizes three variables (not ideal, but straightforward) for computing these heights. One for the vertical border, one for the line-height/font-size/padding dance, and one to add those together.

— Updates CSS across forms and custom forms to use new sizing. Special note here: form validation icon sizing uses the inner variables because background-image doesn't bleed into borders unless explicit background-clip.

* Rename variable $input-border-focus to $input-border-color-focus
* Rename variables $pagination-hover-border, $pagination-active-border, $pagination-disabled-border to $pagination-hover-border-color, $pagination-active-border-color, $pagination-disabled-border-color, respectively
* Rename variables $state-*-border to $state-*-border-color, respectively
* Rename variables $alert-*-border to $alert-*-border-color
* Rename $list-group-active-border to $list-group-active-border-color
* Rename $table-inverse-border to $table-inverse-border-color
* Rename $btn-*-border to $btn-*-border-color
* Rename $navbar-*-toggler-border to $navbar-*-toggler-border-color

* Replace backdrop with simple noop mouse listener

As discussed in https://github.com/twbs/bootstrap/pull/22422 the current
approach of injecting a backdrop (to work around iOS' broken event
delegation for the `click` event) has annoying consequences on
touch-enabled laptop/desktop devices.
Instead of a backdrop `<div>`, here we simply add extra empty/noop
mouse listeners to the immediate children of `<body>` (and remove
them when the dropdown is closed) in order to force iOS to properly
bubble a `click` resulting from a tap (essentially, method 2 from
https://www.quirksmode.org/blog/archives/2014/02/mouse_event_bub.html)
This is sufficient (except in rare cases where the user does manage to tap
on the body itself, rather than any child elements of body - which is not
very likely in an iOS phone/tablet scenario for most layouts) to get iOS to
get a grip and do the correct event bubbling/delegation, meaning the regular
"click" event will bubble back to the `<body>` when tapping outside of the dropdown,
and the dropdown will close properly (just like it already does, even without
this fix, in non-iOS touchscreen devices/browsers, like Chrome/Android and
Windows on a touch laptop).
This approach, though a bit hacky, has no impact on the DOM structure, and
has no unforeseen side effects on touch-enabled laptops/desktops. And crucially,
it works just fine in iOS.

* Remove dropdown backdrop styles

* Update doc for dropdowns and touch-enabled devices

Revert "Drop width from sizing utils given .col- classes can do the same thing (follow up to #22376)"

This reverts commit 2f21403a.

- Pulls in values from v3
- Closes #22371 which didn't use a transition include

- Closes #21622 which kept the 3px
- Puts variable in proper order for shorthand (y x)

Order y & x axis by top, right, bottom, left logic