Windows build instructions: recommend Vcpkg instead of our own WinBuild
As a precondition, check that all our library dependencies are available in the requested version.
At least, we need to update libcerf from 1.13 to 2. A Pull Request to update https://github.com/microsoft/vcpkg/blob/master/ports/libcerf/portfile.cmake might be enough.
Edited by Wuttke, Joachim