Changed gitlab-taskrunner image to gitlab-toolbox

With the name change imposed by CNG!712 (merged), the dsop-scripts need update to build the new image.

This is a quick rename of the gitlab-taskrunner to gitlab-toolbox. I am not seeing anything else that needs to be updated to support gitlab-toolbox. It is expected that the pipeline will fail for this change until CNG!712 (merged) has been merged.

Blocked: CNG!712 (merged)