Add explicit support for passing a `ADD_CMAKE_TO_PATH={0,1}` property to
`msiexec` command-line installations to control the checkbox.  Also
preserve compatibility with the old `ADD_CMAKE_TO_PATH={None,System}`
property, which previously controlled the radio button group, by mapping
the values to the checkbox.

Remove the "Add CMake to the system PATH for the current user" option.
It actually added CMake to the installing user's PATH, not the system
PATH, even though CMake is installed to a system location.

Also revise the wording of the desktop shortcut checkbox to match
the style of the PATH checkbox wording.

Issue: #21465