Implement the UI with a Component Library

## Summary

Make use of a tailwind component library to implement the UI of the admin app and possibly expose those components to the page builder too.

## Objective
- Save time reusing components
- Keep the same look and feel on all pages
- Expose those components on custom pages (those pages are added by users)

## Expected components and elements

Those are the ones we use currently and below a screenshot of the current design.

- Card
- Button
- Navigation / Header
- Sidebar with toggle option
- Pagination
- Tabs
- Alerts
- Icons
- Timeline
- Modal
- Dialog (Confirmation)
- Media Uploader
- Form
- select
- select with multiple options
- input
- textarea

## Screenshot of current design

For reference.

### Card

### Pagination

### Tabs

### Timeline

### Dialog

### Media Uploader

The issue names no files, tests, or entry points. Start by locating the admin app's existing UI and page-builder integration, then compare them with the listed components and screenshots; done means the reusable Tailwind components implement the admin UI and are exposed to custom pages where applicable.

Written by the indexing model from the issue text.