Add some Tutorials on how to enable Screen Mirroring in various OSes

[jbermudes]

As an A/V volunteer, I want to be able to reference how to set up screen mirroring on various OSes like OSX with Touch bar so that when a speaker asks me to help them get their slides mirrored we can do that to get their talk going.

Acceptance Criteria:
Current and N-1 versions of:
OSX, Windows, Ubuntu