[v1] Move block management logic from KVCacheManager to SpecializedManager

[heheda12345]

Should be merged after #17398

To prepare for hybrid allocator, this PR moves logic that need to run for each specialized manager from KVCacheManager to SpecializedManager. As the SpecializedManager not only contains customized logic for different attention type, I renamed it to SingleTypeKVCacheManager.

Prefer to rename specialized_manager.py in a seperate PR.

Didn't move hashing logic (e.g. req_to_block_hashes) to SpecializedManager as the HybridAllocator will do hashing in KVCacheManager level so that different managers with the same block_size can use the same block_hash.

Splitted from #16101

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[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @heheda12345.

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