Add capability to set a custom AeshConsoleCallback implementation

My use case is that I'm only using Aesh for injecting command line arguments, and structuring command classes. I need to control all error output to stdout / stderr, and I need to exit java process with error code when an error occurs. In essence - I only do one REPL cycle, and exit.

Currently the only way to set a custom AeshConsoleCallback is to get a private 'console' field on AeshConsoleImpl, and calling Console.setConsoleCallback() on it. That requires reflection hacks.

Field field = AeshConsoleImpl.class.getDeclaredField("console");
field.setAccessible(true);
Console internalConsole = (Console) field.get(console);
internalConsole.setConsoleCallback(new MyAeshConsoleCallbackImpl(console));