[Feature]: Clean up `vllm.utils`

[DarkLight1337]

🚀 The feature, motivation and pitch

vllm/utils/__init__.py has >3k lines with a long list of imports. This is not ideal for the following reasons:

• This file, being imported by many files in vLLM while also importing many external modules, makes it very difficult to defer expensive imports.
• The risk of merge conflicts is high whenever two PRs change this file, especially when imports are updated.
• The code because less organized.

We should split this up into multiple files under vllm/utils directory, where each file has a theme that can be used to group the various utility functions. Also, downstream code should import specific submodules of vllm.utils instead of the root vllm.utils to make deferring imports easier.

Alternatives

No response

Additional context

cc @hmellor @mgoin @youkaichao

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[iAmir97]

Is anyone working on this? if not I will pick it up

[DarkLight1337]

You can refer to the PRs linked in this issue to see which items have already/are being done.