The `gitea.com/go-chi/cache` package only exists for Gitea, so it moves
into `modules/cache`.
- `ITEM_TTL = -1` disables caching as documented
- Sub-second TTLs round up instead of never expiring
- The Redis adapter no longer grows a `MacaronCache` hash
- Use two-queue cache for in-memory cache
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
