Added custom cacheManager and cache key

[rignaneseleo]

Summary

This PR addresses issue #47 by introducing the ability to pass a custom cacheManager and cacheKey as parameters. This makes the library more flexible and customizable, similar to how CachedNetworkImage handles caching.

Key Changes

• Added support for passing cacheManager and cacheKey parameters.

• This allows developers to:

  • Use custom cache managers tailored to their specific needs.
  • Preload videos from different sources using the same cacheManager and cacheKey for efficient caching.

• Removed the _storage variable, as it was redundant. The cacheManager already tracks cache expiry dates and manages cached items, making additional storage management unnecessary.

Advantages

• Preload videos from anywhere
• Greater flexibility in cache management.
• Streamlined and simplified code by removing redundant storage handling.
• Easier integration with preloaded media files.

Thank you for reviewing!