Window Manager: Also support macOS and Linux

Currently the window manager actions are written for Windows. We should also support macOS and Linux. It's mostly a matter of porting [these methods](https://github.com/reibitto/command-center/blob/70ca2b716ff3569b83b59b95076728cc0a09d68b/emulator-core/src/main/scala/commandcenter/GlobalActions.scala) and adding cases for `OS.MacOS` and `OS.Linux`.