Add IIconCacheProvider abstraction with disk and in-memory implementation

[ivanmarkovic1402]

No description provided.

[gemini-code-assist]

Code Review

This pull request introduces an extensible caching mechanism for content type icons by defining an IIconCacheProvider interface and providing both in-memory and disk-based implementations. The feedback focuses on enhancing the robustness and performance of these changes. Key recommendations include implementing key-based locking in DiskIconCacheProvider to ensure thread-safe file operations, handling potential file corruption during image loading, and using Path.Combine for safer path construction. Additionally, the reviewer suggests optimizing memory usage in ContentTypeIconService by removing a redundant image clone, and increasing the flexibility of the dependency injection registration by supporting custom service lifetimes.

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