Add use cache example with external persistence beyond in-memory store #1409

• related to Research "use cache" cache invalidation strategy during dev #1395

Currently the examples (both examples/use-cache and examples/use-cache-callbable) demonstrates use cache runtime mechanism with the focus on its composition capability (by RSC API) and use server integration capability with in-memory cache. The demo is sufficient for that exact purpose but when external persistence is involved in practice, it likely arises new requirement on transform-level features such as #1395. We should create a standalone example so we can verify and confirm the hypothesis as we explore the topic.