cubicweb-vcreview #4514651 port to vcsfile 2 [validation pending]

and ensure we use hglib

prioritynormal
typetask
done in2.0.0
load1.000
load left0.000
closed by#bbd93c3b8b17 Port to vcsfile 2.0 and use hglib in tests (closes #4514651)
patchPort to vcsfile 2.0 and use hglib in tests [applied]