[Prototype][WIP] Prefix Cache Aware Scheduling for V0

[rickyyx]

FIX #7883 in V0

[github-actions]

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[rickyyx]

Main changes plz take a look

• block manager
• scheduler
• sequence

Please ignore the test codes for now. cc @comaniac

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. @rickyyx please rebase it. https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[rickyyx]

Still in draft - but running CIs for some early correctness signals.

[rickyyx]

Merged in #10128

Remaining items in this PR not being merged:

• Inject block hash into the block at block creation rather having the block owning it (already done in V1)
• Remove token ids from block if the hash is not computed by the block itself (already done in V1)
• Lora support