refactor: move go-chi/cache into Gitea (#39530)

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>

custom/conf/app.example.ini

@@ -1981,7 +1981,7 @@ LEVEL = Info
 ;; Either "memory", "redis", "memcache", or "twoqueue". default is "memory"
 ;ADAPTER = memory
 ;;
-;; For "memory" only, GC interval in seconds, default is 60
+;; For "memory" and "twoqueue", GC interval in seconds, default is 60
 ;INTERVAL = 60
 ;;
 ;; For "redis" and "memcache", connection host address