yuzu/main: Add basic command line arguments

The following command line arguments are supported:

yuzu.exe "path_to_game" - Launches a game at "path_to_game"
yuzu.exe -f - Launches the next game in fullscreen
yuzu.exe -g "path_to_game" - Launches a game at "path_to_game"
yuzu.exe -f -g "path_to_game" - Launches a game at "path_to_game" in fullscreen