Add onboarding step - getting set up on git & github

[KirstieJane]

I'm working through getting git & github set up with @minnieho1115 today and it occurs to me that this should be a meeting that I have with every new lab member.

• Install github desktop (unless you're confident with the command line)
• Install git bash (if on windows) & setup user name and email
• Install a text editor - I recommend vs code

Good to then demo the links between all of these three and how they stay in sync.