feat: Add Storybook for component documentation, testing, and development (#34907)

Co-authored-by: Echo <ChaosExAnima@users.noreply.github.com>
Co-authored-by: Renaud Chaput <renchap@gmail.com>

.storybook/storybook-theme.ts

@@ -0,0 +1,7 @@
+import { create } from 'storybook/theming';
+
+export default create({
+  base: 'light',
+  brandTitle: 'Mastodon Storybook',
+  brandImage: 'https://joinmastodon.org/logos/wordmark-black-text.svg',
+});