fix(router): add preserve_host logic in stream subsystem

[chronolaw]

Summary

It is a succeeding of #12127.

• add paths = { "/" } in routes to enable calculation cache for path
• add perserve_host logic for stream

KAG-3032

Checklist

• The Pull Request has tests
• A changelog file has been created under changelog/unreleased/kong or skip-changelog label added on PR if changelog is unnecessary. README.md
• There is a user-facing docs PR against https://github.com/Kong/docs.konghq.com - PUT DOCS PR HERE

Issue reference

Fix #[issue number]

[chronolaw]

It will be replaced by #12268 .

[team-gateway-bot]

Cherry-pick failed for master, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally.

git remote add upstream https://github.com/kong/kong-ee
git fetch upstream master
git worktree add -d .worktree/cherry-pick-12261-to-master-to-upstream upstream/master
cd .worktree/cherry-pick-12261-to-master-to-upstream
git checkout -b cherry-pick-12261-to-master-to-upstream
ancref=$(git merge-base 8c2b5a4e7a35da88bbbd5b78507b8a292597d420 943ea268e2dc03c71124a98921590d6a298ecb5f)
git cherry-pick -x $ancref..943ea268e2dc03c71124a98921590d6a298ecb5f