Merge topic 'command-line-argument-bool'

62f4a41647 Refactor: Use cmCommandLineArgument::setTo{True,Value}()
0645d08c98 cmCommandLineArgument: Add setToTrue() and setToValue() helpers

Acked-by: Kitware Robot <kwrobot@kitware.com>
Tested-by: buildbot <buildbot@kitware.com>
Acked-by: Robert Maynard <robertjmaynard@gmail.com>
Merge-request: !7181