Support to work on one configuration only

[tllv]

I'm missing an option to run on a certain configuration e.g "Linux|x64".

Background: We have a large solution with about 50% of the projects used for Windows and Linux builds. I'm exploring several ways to change our very old Linux build system into a modern way. I want to run the cmakeconverter on the Linux configuration only. Cmake files of the Windows parts would not be used. And by the way the converter crashes because of the Qt addin commands, but I already found another bug report about this. The Linux configuration does not include those commands.