ci: Auto-cleanup gitlab-workhorse packages after 30 days

What does this MR do and why?

Similarly to !100205 (merged), this will make sure gitlab-workhorse packages are cleanup up after 30 days.

I chose 30 days because these packages are built less frequently that the assets one, so we can keep them longer (we currently have 118 gitlab-workhorse packages).

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.