Implement PrepareDataPlugin for prefix cache match plugin

[rahulgurnani]

What type of PR is this?

/kind feature

What this PR does / why we need it:

This PR implements PrepareDataPlugin hook for prefix cache match plugin. The goal is to split the prefix cache match plugin into match plugin and scorer. So, the PR adds a new scorer plugin to be used alongside the prepare data prefix cache match plugin for scoring.
This is an intermediate step towards migration of the plugin.

Did some initial scale testing using vllm:

@kaushikmitr / @BenjaminBraunDev FYI

Which issue(s) this PR fixes:

Fixes #1924

Does this PR introduce a user-facing change?:

yes. this PR adds a new feature flag "prepareDataPlugins"

[k8s-ci-robot]

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[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: rahulgurnani
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