Commandline instructions for setup guide

[tarik-celik]

Hello, I added commandline instructions for linux setup guide. I felt like it was needed because, not everyone uses gnome or kde plasma. Also i removed the paranthesis from name of dektop enviroments; for any desktop enviroment can installed in any linux disturbution. Feel free to edit as you like.

[RebeccaTamachiro]

Hi @tarik-celik 👋 Thanks for raising this. I have brought this up internally with the team and will come back with some updates soon.