Add verbosity flag to gmclash - off by default

This MR adds a verbosity flag to gmclash and sets it off by default. It addresses the issue #25 (closed) from the ITk developers.

added FullSimLight label

mentioned in issue #25 (closed)

enabled an automatic merge when the pipeline for f6d3e3fc succeeds

canceled the automatic merge

mentioned in commit 9a18dfdd

merged