Add a fact checker feature with updated styling (#835)

- Add an experimental feature used for fact-checking falsifiable statements with customizable models. See attached screenshot for example. Once you input a statement that needs to be fact-checked, Khoj goes on a research spree to verify or refute it.
- Integrate frontend libraries for [Tailwind](https://tailwindcss.com/) and [ShadCN](https://ui.shadcn.com/) for easier UI development. Update corresponding styling for some existing UI components. 
- Add component for model selection 
- Add backend support for sharing arbitrary packets of data that will be consumed by specific front-end views in shareable scenarios

src/interface/web/app/page.tsx

@@ -2,7 +2,7 @@ import styles from "./page.module.css";
 
 export default function Home() {
   return (
-    <main className={styles.main}>
+    <main className={`${styles.main} text-3xl font-bold underline`}>
       Hi, Khoj here.
     </main>
   );