refactor: Replace Rollup with Vite (#2656)

This is a high risk change: every byte the card ships is emitted by a
different bundler, minified by a different minifier, and every
stylesheet is compiled by a different sass. The intent is that the
card's behaviour is unchanged.

**Significant development win**: Build time drops from 24s to 1.1s 🎉 

Also adds a test suite ('dist') that runs against the built bundle.

src/scss/card.scss

@@ -1,5 +1,5 @@
 @use './themes/base.scss';
-@import './z-index.scss';
+@use './z-index.scss' as *;
 
 :host {
   display: block;

src/scss/drawer-inject.scss

@@ -1,4 +1,4 @@
-@import './z-index.scss';
+@use './z-index.scss' as *;
 
 :host {
   // Drawer width sizes to contents.

src/scss/effects.scss

@@ -1,4 +1,4 @@
-@import './z-index.scss';
+@use './z-index.scss' as *;
 
 :host {
   display: block;

src/scss/themes/base.scss

@@ -1,6 +1,6 @@
-@import 'dark.scss';
-@import 'light.scss';
-@import 'traditional.scss';
+@use 'dark.scss' as *;
+@use 'light.scss' as *;
+@use 'traditional.scss' as *;
 
 :host {
   /*********