Centralize authentication logic and integrate token refresh mechanism

- Introduce `AuthWrapper` component for streamlined session-based layouts and authentication handling.
- Add new utilities (`tokenUtils.ts`) for JWT decoding, token expiration checks, and refresh operations via Keycloak.
- Refactor `serverCall` and `authOptions` to use centralized token refresh logic, removing redundant implementations.
- Implement `ClientSessionProvider` for consistent session management across the client application.
- Simplify `RootLayout` by delegating authentication enforcement to `AuthWrapper`.

internal_frontend/components/ClientSessionProvider.tsx

@@ -0,0 +1,12 @@
+"use client";
+
+import {SessionProvider} from "next-auth/react";
+import React from "react";
+
+interface Props {
+    children: React.ReactNode;
+}
+
+export function ClientSessionProvider({children}: Props) {
+    return <SessionProvider refetchInterval={180}>{children}</SessionProvider>;
+}