draft proposal on provenance-qualified dependencies

[Gershom B]

Hey all, I mentioned (on the long SLURP thread) that I was thinking
about a general proposal for provenance-qualified dependencies to
reduce coupling in the haskell ecosystem. Having worked it out a bit,
I think the bigger win is it also provides a way to specify
dependencies on git repos, etc., which has been an oft-requested
feature.

I don't want to submit it as an ecosystem proposal proper without
further polish, and I held off on bugging a larger audience of cabal
folks until the 2.2 branch was cut. So now I'm passing this along for
further comment and polish before I make a real proposal:
https://github.com/gbaz/ghc-proposals/blob/patch-1/proposals/0000-provenance-qualified-imports.rst

There's no urgency, but it would be good to get some feedback in the
next few weeks if possible.

Cheers,
Gershom