build: add npx to zip and 7z packages

Copy npx and npx.cmd from `deps\npm\bin` for consistency with .msi
package.

PR-URL: https://github.com/nodejs/node/pull/15033
Refs: https://github.com/nodejs/node/pull/14235


Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>