feat(clustering/rpc): add support for cert details

[chronolaw]

Summary

KAG-6084
This PR follows #14046.

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]

[dndx]

Should we update the spec file as well?

[chronolaw]

Should we update the spec file as well?

No, we did not change rpc spec.

[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-14050-to-master-to-upstream upstream/master
cd .worktree/cherry-pick-14050-to-master-to-upstream
git checkout -b cherry-pick-14050-to-master-to-upstream
ancref=$(git merge-base 8e14a18c4d56bd726833ecf305c56fbf209ed943 477c37377d7ca59c5d617a1b0adcf2495c0cf2d5)
git cherry-pick -x $ancref..477c37377d7ca59c5d617a1b0adcf2495c0cf2d5