Add horizontal list group modifier (#27970)

Alternate take to #27683 that builds the modifier class based on min-width, such that list groups are stacked until the class's breakpoint is reached. This is less verbose, matches our primary responsive approach, and prevents an extra class. Unfortunately, I believe supporting flush list groups is too much code here, so I've skipped that and made a note in the docs.

Also added examples generate from our breakpoints data file with a protip for how to do equal width items.

package.json

@@ -174,11 +174,11 @@
     },
     {
       "path": "./dist/css/bootstrap.css",
-      "maxSize": "25 kB"
+      "maxSize": "25.5 kB"
     },
     {
       "path": "./dist/css/bootstrap.min.css",
-      "maxSize": "22.7 kB"
+      "maxSize": "23.5 kB"
     },
     {
       "path": "./dist/js/bootstrap.bundle.js",