RFC: Change the default shell within GNOME OS

The current default shell we ship in the VM images provides a very poor UX. It does not show any relevant information to the user - only the shell name. It also lacks things like in-depth auto-completion or highlighting.

I'd like to propose changing the default shell, or even the shell prompt, to one that provides more information and better empowers those using GNOME OS for design, development, and testing.

Some options:

• Changing the bash prompt - we can get something marginally more informative and helpful this way
• Using zsh - very powerful, though requires setup for a decent experience