Feature Request: Allow passing a repository with dotfiles

[felladrin]

Is your feature request related to a problem? Please describe the solution you'd like.

It would be great to have dotfiles installed automatically like we can do on gitpod.io.

Screenshot from https://gitpod.io/preferences:

Maybe we could pass the repo as an argument for run-gp.

Describe alternatives you've considered

We can manually clone the dotfiles repo and execute the install script once we're in the environment. But if we could automate it and save some time, run-gp would be even better!