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/package.json

@@ -17,15 +17,28 @@
     "windowsexport": "yarn build && xcopy out ..\\..\\khoj\\interface\\built /E /Y && yarn windowscollectstatic"
   },
   "dependencies": {
+    "@radix-ui/react-alert-dialog": "^1.1.1",
+    "@radix-ui/react-dialog": "^1.1.1",
+    "@radix-ui/react-label": "^2.1.0",
+    "@radix-ui/react-slot": "^1.1.0",
     "@types/katex": "^0.16.7",
     "@types/markdown-it": "^14.1.1",
+    "autoprefixer": "^10.4.19",
+    "class-variance-authority": "^0.7.0",
+    "clsx": "^2.1.1",
     "katex": "^0.16.10",
+    "lucide-react": "^0.397.0",
     "markdown-it": "^14.1.0",
     "markdown-it-highlightjs": "^4.1.0",
     "next": "14.2.3",
+    "postcss": "^8.4.38",
     "react": "^18",
     "react-dom": "^18",
-    "swr": "^2.2.5"
+    "shadcn-ui": "^0.8.0",
+    "swr": "^2.2.5",
+    "tailwind-merge": "^2.3.0",
+    "tailwindcss": "^3.4.4",
+    "tailwindcss-animate": "^1.0.7"
   },
   "devDependencies": {
     "@types/node": "^20",