Generate csproj/fsproj files from bazel targets

[purkhusid]

This is feature request which I might tackle myself later if nobody else does it.
I would like to be able to generate .fsproj/csproj files from the C#/F#` targets that are declared in my workspace.

This would make it easier to keep the IDE support working without having to manually maintain the .fsproj/.csproj files.

[njlr]

I made a start on this here: https://github.com/njlr/bazel2proj

There is still lots to do, but it works for the examples in the repo.

Long term I think it would be best to bring the tool into here?

[purkhusid]

Nice! It's definitely on the roadmap to ass BUILD/csproj/fsproj generation. I'll take a look at this once I'm off vacation.

[purkhusid]

Duplicate of #258