Support to manually trigger CacheStore._cleanupCache()

## 🚀 Feature Requests

Support to manually trigger CacheStore._cleanupCache()

### Describe the feature
In current CacheStore implementation _cleanupCache() function is triggered 10 seconds later after every call to CacheStore.retrieveCacheData function. That means; if we don't request a new -not yet cached uri-, retrieveCacheData function will not be triggered, so there is no way that _cleanupCache logic have a chance to run again.

As I understand correctly; in current implementation there is no way to get a new version of an already cached url resource till we request a new uri resource to trigger cleanup logic.

### Platforms affected (mark all that apply)
- [x] :iphone: iOS
- [x] :robot: Android

Start by tracing CacheStore.retrieveCacheData and the delayed _cleanupCache() call to understand when cleanup currently runs. Define the manual trigger's expected behavior for already cached URLs, then verify that cleanup can be invoked without requesting a new URI and cover the behavior with the relevant cache-store tests.

Scritto dal modello di indicizzazione a partire dal testo della issue.