add support for new login method

[cq674350529]

Login method has been changed since 6.43. So add support for it in winbox communication and keep the remaining unchanged.

Also, we can use the new login method direcly, like execute_milo does.

[jacob-baines]

Thanks @cq674350529! I'm traveling a bit so this will sit around for a few days before I get a good look at it. But yeah, good PR. I was super lazy about only putting the login in milo 😬

[cq674350529]

Take your time! Learnt a lot from both your slides and codes 😄 .