The IDE support in OpenJDK unfortunately leaves a lot to be desired. There have been a garden variety of attempt to support a specific IDE for a specific part of the code base, cluttered all over the code base.

This patch is a first attempt go get a one ring, eh, structure, to rule them all.

I have moved all IDE project creators into the following structure:
make/ide/<ide>/<part of the code>
where <part of the code> is one of currently "hotspot", "langtools" or "jdk", and <ide> is one of "vscode", "idea", "netbeans" or "vistualstudio".

This will not magically improve IDE support, but will at least make it clearer what we have and what we are missing.