Introduce cache clear mechanism for AppInfo storage

[shuuji3]

We need the TTL cache or other way to clear cache for AppInfo storage to solve the permanent cache issue that locks out all users in the server with certain conditions (ref. #2279 #2562 #2422).

For TTL, Elk uses unstorage as a storage interface and has several storage drivers (memory, cloudflare, vercel, fs), but only a few drivers support TTL functionality.

• Some storage drivers (like Cloudflare) already support for its TTL feature: https://unstorage.unjs.io/drivers/cloudflare
• Memory driver has a new PR for TTL, which was opened just last week: feat: add meta and ttl to memory driver (new driver) unjs/unstorage#583

Maybe we need to implement our own TTL functionality with the package like @isaacs/ttlcache or need to wait for updates from upstream unstorage.

[shuuji3]

The first one (generic TTL feature for some drivers) was implemented by #3193. But the upstream memory driver PR is still waiting to be reviewed.

If I understand correctly, now AppInfo will be cleared from the TTL-supported storage driver after 1 week, and the memory driver will still hold the cache forever. But it's a volatile memory driver so it should be cleared when a new instance is created, so a new deployment or server restart will also clear the AppInfo cache now.