Implement possibility to minimize Carla to the system tray

[ranolfi]

Hello,

First, thank you so much for the respectable software you've built.

I normally have Carla launched upon login, as it is part of my audio stack (PulseAudio <-> JACK2 <-> ALSA). As such I always have it running. For the longest time I've been keeping its window on a separate, unused "workspace", but ideally, I'd like to be able to minimize/close it to the tray (similar to Cadence). Can this be implemented?