Allow CI for external contributors.
Getting this to work will involve modifying my CI templates in xcookie (https://github.com/Erotemic/xcookie) to move to a "rules" based approach instead of the deprecated "only" and "except" gitlib-ci yaml-isms. I don't want to use gitlab includes if possible. I do prefer native YAML anchors as fraught as they be.
For security, CI from external contributions needs to require a manual run button to be hit.
References I've been given to help:
Edited by Jon Crall