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

Prevent mixin media-breakpoint-only from breaking when supplying the
first or last entry in $grid-breakpoints.

close #22338 by putting h4 text within links, but keep headings as is because i can't justify writing h3.h4 

wrap .bd-navbar position styles in supports query, remove prefix, and update linter settings for file