[Feat] KV cache aware routing

[YuhanLiu11]

This PR adds the feature of KV cache aware routing with LMCache's KV cache controller. Based on the tokenized prompt, the KV cache controller will return the best instance ID that contains the KV cache for the prompt in it.

Currently, only local version is supported, helm chart support for KV cache aware routing is coming soon.

BEFORE SUBMITTING, PLEASE READ THE CHECKLIST BELOW AND FILL IN THE DESCRIPTION ABOVE

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• Try to classify PRs for easy understanding of the type of changes, such as [Bugfix], [Feat], and [CI].

Detailed Checklist (Click to Expand)

Thank you for your contribution to production-stack! Before submitting the pull request, please ensure the PR meets the following criteria. This helps us maintain the code quality and improve the efficiency of the review process.

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Please try to classify PRs for easy understanding of the type of changes. The PR title is prefixed appropriately to indicate the type of change. Please use one of the following:

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