Create Settings Menu

[ajbowler]

As more features come into play we'll want a settings menu.

Create a settings menu that can be accessed via main menu (#6) and port all scoreboard related command line args to it, then remove the command line args.

The rpi-rgb-led-matrix command line args will stay as command line args.

[ajbowler]

Closing this, we've ended up going through the config file route, so a settings menu is pretty unnecessary and confusing as it creates more than one way to do things.