add prioritize active screen option for activating Application Launcher

Adds an option that changes the behaviour of the 'activateLauncherMenu' shortcut so that it prioritizes the active screen when searching for a launcher, instead of prioritizing the primary screen.

It's been bugging me since I got a secondary monitor that I can't use the meta key to open the application launcher on my currently active monitor, and that it instead always opens the one on the primary monitor, so here's my attempt at adding an option to fix that.