Integrate ProfileDropdown component, update layout to include user menu, and add Keycloak logout API route.

main-website/app/api/logout/route.ts

@@ -0,0 +1,11 @@
+import {NextResponse} from 'next/server'
+
+export async function POST() {
+    const keycloakLogoutUrl = process.env.KEYCLOAK_LOGOUT_URL
+
+    if (!keycloakLogoutUrl) {
+        return new NextResponse('Missing KEYCLOAK_LOGOUT_URL env variable', {status: 500})
+    }
+
+    return NextResponse.redirect(keycloakLogoutUrl, 302)
+}