Upstream sync v0.4.0.post1 (merged with upstream-v0.4.0.post1)

[mgoin]

Merge upstream v0.4.0.post1 into aka branch 'upstream-v0.4.0.post1'

Rough commands used:

git remote add upstream https://github.com/vllm-project/vllm.git
git fetch upstream
git fetch origin
DATE=$(date '+%Y-%m-%d')
LOCAL_BRANCH=upstream-sync-${DATE}
git checkout upstream/main
git checkout a3c226e7eb19b976a937e745f3867eb05f809278 # this is v0.4.0.post1
git checkout -b upstream-v0.4.0.post1
git checkout main
git merge upstream-v0.4.0.post1

Ran ./format.sh on all the files - this was required because isort was added and needed to change import orders for most files

TEST PLAN
Nightly