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/common/auth.ts

@@ -0,0 +1,23 @@
+'use client'
+
+import useSWR from 'swr'
+
+export interface UserProfile {
+    email: string;
+    username: string;
+    photo: string;
+    is_active: boolean;
+    has_documents: boolean;
+}
+
+const userFetcher = () => window.fetch('/api/v1/user').then(res => res.json()).catch(err => console.log(err));
+
+export function useAuthenticatedData() {
+
+    const { data, error } = useSWR<UserProfile>('/api/v1/user', userFetcher, { revalidateOnFocus: false });
+
+    if (error) return null;
+    if (!data) return null;
+
+    return data;
+}