Update build instructions for Windows

[KasNotten]

I would like to propose adding the following details to the instructions for building maven-mvnd on Windows.
I had to spend some time figuring out which tools I needed and I figured I would save other future Windows contributors the trouble.

[mthmulders]

It confuses me that the build fails, but only on Ubuntu, for something that's only a documentation change. @gnodet / @ppalaga, any objections on merging it, despite the failing build?

[gnodet]

It confuses me that the build fails, but only on Ubuntu, for something that's only a documentation change. @gnodet / @ppalaga, any objections on merging it, despite the failing build?

Some tests are flaky. When that's the case, I usually re-run them to have green lights...