Darcs walker

[toastal]

Is your feature request related to a problem? Please describe.

I am using Darcs as my current DVCS of choice while Pijul is still lacking some features. It appears Git & Jujutsu are supported, but Darcs is not.

Describe the solution you'd like

Implement darcs/darcs.go

Describe alternatives you've considered

Usu one of the two supported VCSs, tho this gives up Patch Theory

Additional context