[WIP] [V1] VLM hashing and mapper caching

[alexm-neuralmagic]

This PR is the first step towards caching of VLM images and skipping of the encoder execution. Currently it adds:

1. Hashing support for images
2. Simple LRU cache based on OrderedDict
3. Caching of MM mapper results

TODO:

1. Integrate with Ricky's KVCacheManager refactor
2. Skip the encoder execution for cached embeds

[github-actions]

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[comaniac]

@alexm-neuralmagic is it possible to break this PR to 2 PRs so that we could merge the mm_hash sooner to unblock the embedding cache?

The current PR seems already has this functionality, so if you could add unit tests we should be good.

Also cc @yue-anyscale

[alexm-neuralmagic]

@comaniac yeah will try to break the PR to 2 pieces.

[alexm-neuralmagic]

Depends on #11020

[alexm-neuralmagic]

Not necessary anymore, replaced by #11020