Add setting `show_console_window`

... it can be used on Windows and Mac to show a console window besides the GUI app. As usual, you can set it in src/build/settings/windows.json, .../mac.json or .../base.json. It has no effect on Linux though, so the latter is not the best way.

Also removed the parameter extra_pyinstaller_args from the various freeze_windows(...), freeze_mac(...), etc. functions. If you used these functions and the parameter, you'll have to revert to fbs.freeze.run_pyinstaller(...) instead. But nobody seemed to be using the parameter, and so the change should not affect anyone.