Add a CMake command line argument that would allow building multiple configs in one go

The CMake command line allows invoking the underlying generator tool via

cmake --build .  # calls make / jom / ninja

You can also specify which Configuration to build for if it's supported by the generator (like MSBuild or Xcode).

cmake --build . --config Release
cmake --build . --config Debug

It would be useful if CMake allowed a way to build multiple or all configurations in one single command invocation, something similar to:

cmake --build . --config Release --config Debug

or

cmake --build .  --config all