Migrate "Core work: XYZ" issue tracking to labels

On the sidebar of Redmine we have a bunch of "Core work: XYZ" custom queries. Each of them lists issues that block a specific tracking ticket. we won't have blocking relationship in GitLab so, in order not to lose this important information, we need to encode it differently.

I propose having one label per such custom query and setting that label to every migrated issue that blocks the corresponding tracking ticket. For example, there would be a "Core work: Foundations Team" label, set on each issues that blocks #16209.