Move artifact promotion from SharedActions to GradleUtils

[Jonathing]

Currently, SharedActions is completely responsible for promoting artifacts that have been published to our maven. While it's been working well, this can cause an issue if there is a problem with publishing or if the artifact has changed in some unexpected way that wasn't accounted for in the related project's repository. So, the solution would be to move this promotion to GradleUtils and add it as a finalization of the publishing to forge maven.

This also has the added benefit of alerting us to any issues caused by artifact promotion failures, instead of us having to find out late when a new artifact isn't being promoted on the files site.