Merge topic 'generate-cmake-build-command-parallel'

d2b856bc92 ctest_build: Add the PARALLEL_LEVEL argument
fc2ac46043 build_command: Add the PARALLEL_LEVEL argument
4dd4e9dd6c cmGlobalGenerator: Add parallel parameter to GenerateCMakeBuildCommand

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: Brad King <brad.king@kitware.com>
Merge-request: !6069