child_process: add windowsHide option

This commit exposes the UV_PROCESS_WINDOWS_HIDE flag in Node
as a windowsHide option to the child_process methods. The
option is only applicable to Windows, and is ignored elsewhere.

Fixes: https://github.com/nodejs/node/issues/15217
PR-URL: https://github.com/nodejs/node/pull/15380


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>