Sound suppression in GKC

Allow Play Sound to be suppressed via a checkbox on the GKC component - just as reports can be suppressed. Multiple sounds emanating from pieces actioned by a GKC can be problematic. It would be useful sometimes to prevent that in a simple straightforward way.

Bonus request: Allow a sound file to be specified on the GKC, just as a report can be specified.

Logged as GitHub issue #10822