D7311: utils: move the `dirs` definition in a dedicated module (API)

[marmoute (Pierre-Yves David)]

marmoute added inline comments.

INLINE COMMENTS

> martinvonz wrote in dirstateutil.py:14
> Is `pathutil.py` an appropriate home for this instead of creating a new file?

I feel like `pathutil.py` is mostly scm agnostic and I would rather keep it this way.

REPOSITORY
  rHG Mercurial

CHANGES SINCE LAST ACTION
  https://phab.mercurial-scm.org/D7311/new/

REVISION DETAIL
  https://phab.mercurial-scm.org/D7311

To: marmoute, durin42, martinvonz, #hg-reviewers, Alphare, indygreg
Cc: indygreg, mercurial-devel