[backport] Add benchmark for the number of minimum cpu cores (#5127)

[alexggh]

This backports #5127, to the stable branch.

Unfortunately https://polkadot.subsquare.io/referenda/1051 passed after the cut-off deadline and I missed the window of getting this PR merged.

The change itself is super low-risk it just prints a new message to validators that starting with January 2025 the required minimum of hardware cores will be 8, I see value in getting this in front of the validators as soon as possible.

Since we did not release things yet and it does not invalidate any QA we already did, it should be painless to include it in the current release.

(cherry picked from commit a947cb8)

[github-actions]

This pull request is amending an existing release. Please proceed with extreme caution,
as to not impact downstream teams that rely on the stability of it. Some things to consider:

• Backports are only for 'patch' or 'minor' changes. No 'major' or other breaking change.
• Should be a legit fix for some bug, not adding tons of new features.
• Must either be already audited or not need an audit.

Emergency Bypass

If you really need to bypass this check: add validate: false to each crate
in the Prdoc where a breaking change is introduced. This will release a new major
version of that crate and all its reverse dependencies and basically break the release.

[ggwpez]

Agree that this is very low-risk since it modifies a single console command and should not restart QA testing.