docs: init Realtime authz docs

apps/docs/components/Navigation/NavigationMenu/NavigationMenu.constants.ts

@@ -1285,6 +1285,11 @@ export const realtime: NavMenuConstant = {
         },
       ],
     },
+    {
+      name: 'Security',
+      url: undefined,
+      items: [{ name: 'Authorization', url: '/guides/realtime/authorization' }],
+    },
     {
       name: 'Guides',
       url: undefined,