feat(authentication): add custom routine, and documentation

packages/wyatt_authentication_bloc/example/lib/presentation/features/sub/sub_page.dart

@@ -35,14 +35,20 @@ class SubPage extends StatelessWidget {
               icon: const Icon(Icons.logout_rounded)),
           IconButton(
               onPressed: () =>
-                  context.read<AuthenticationRepository<int>>().refresh(),
+                  context.read<AuthenticationCubit<int>>().refresh(),
               icon: const Icon(Icons.refresh))
         ],
       ),
-      body: const Padding(
-        padding: EdgeInsets.all(8),
-        child: SingleChildScrollView(
-          child: Text('Another page'),
+      body: Padding(
+        padding: const EdgeInsets.all(8),
+        child: ListView(
+          children: [
+            const Text('Another page'),
+            ElevatedButton(
+              onPressed: () => context.read<AuthenticationCubit<int>>().delete(),
+              child: const Text('Delete account'),
+            ),
+          ],
         ),
       ),
     );