[Misc] Split monolithic config.py into domain-specific modules

[jeejeelee]

Background

Currently, the vLLM configuration is concentrated in a single large config.py containing over 5000 lines of code with multiple interconnected dataclasses. This monolithic structure has poor maintainability and readability, making it difficult for developers to locate, understand, and modify specific configurations.

Solution

This PR splits the monolithic configuration file into focused, domain-specific modules to improve code organization and developer experience.

|-- __init__.py
|-- cache_config.py
|-- compilation_config.py
|-- decoding_config.py
|-- device_config.py
|-- kvevents_config.py
|-- kvtransformer_config.py
|-- load_config.py
|-- lora_config.py
|-- model_config.py
|-- multimodal_config.py
|-- obervability_config.py
|-- parallel_config.py
|-- pass_config.py
|-- pooler_config.py
|-- promptadapter_config.py
|-- scheduler_config.py
|-- speculative_config.py
|-- tokenizerpool_config.py
|-- utils.py
|-- vllm_config.py

[github-actions]

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[mergify]

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

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[mergify]

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

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[houseroad]

I like the idea to break a big file into smaller modules. One thing we may consider is the backward compatibility. Like we can import necessary modules in vllm/config/init.py, so we don't need to change imports like "from vllm.config import TaskOption, _get_and_verify_dtype"

[mergify]

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

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork