[ofiwg] provider feature matrix

[Hefty, Sean]

> I think it would be worthwhile to keep the 1.2.1 data (e.g., make a new
> wiki page with "1.2.1" in the filename somehow.  I.e., we have the data,
> so we might as well keep it -- especially in early days of libfabric, it
> may well be useful (user asks, "I'm using libfabric vX.Y, but Z doesn't
> work..." / "Oh, you should upgrade to vA.B; the matrix shows that Z isn't
> support in vX.Y").
> 
> And we should keep https://github.com/ofiwg/libfabric/wiki/Provider-
> Feature-Matrix to always be the current release.

I agree with this as well.