Implemented KVCacheAwareScorer

[vMaroon]

Summary

Implemented KVCacheAwareScorer which uses kvcache.Indexer as an embedded module.
The latter is configured with default configuration + an env settable Redis server address, and a HuggingFace token which is an acceptable practice.

Changes:

• This PR introduces some changes to the scheduler flow since this is the first scorer that has to be prompt-aware.
• This PR also introduces minor code refactoring to the previous work.
• The Dockerfile was changed:
  • An implication of embedding the kvcache.Indexer directly is having to statically link the HuggingFace Rust tokenizer's Go bindings.
  • Due to the kvcache-manager repo being internal, having Go download its modules requires configuring access. Therefore GIT_NM_USER and NM_TOKEN have to be set.
• The Makefile's image-build target was slightly refactored and updated to support the Dockerfile changes, and building from non amd64 archs.

Follow-up work:

• Scorers configuration

[vMaroon]

The force-push rebases onto dev and reimplements the KVCacheScorer along with the new missing logic.

[vMaroon]

The force push undos a nolint directive that failed to fix the buggy CI linting. The linting error makes no sense, I think we can ignore it or followup later.