Add our first view via Next.js for Agents (#817)

Initialize our migration to use Next.js for front-end views via Agents. This includes setup for getting authenticated users, reading in available agents, setting up a pop-up modal when you're clicking on an agent, and allowing users to start new conversations with agents.

Best attempt at an in-place migration, though there are some noticeable differences.

Also adds view for chat that are not being used, but in experimental phase.

src/interface/web/app/agents/layout.tsx

@@ -0,0 +1,25 @@
+
+import type { Metadata } from "next";
+import NavMenu from '../components/navMenu/navMenu';
+import styles from './agentsLayout.module.css';
+
+export const metadata: Metadata = {
+    title: "Khoj AI - Agents",
+    description: "Use Agents with Khoj AI for deeper, more personalized queries.",
+    icons: {
+        icon: '/static/favicon.ico',
+    },
+};
+
+export default function RootLayout({
+    children,
+}: Readonly<{
+    children: React.ReactNode;
+}>) {
+    return (
+        <div className={`${styles.agentsLayout}`}>
+            <NavMenu selected="Agents" />
+            {children}
+        </div>
+    );
+}