win,msi: set install directory permission

Explicitly set permission for Windows install directory.

Refs: https://hackerone.com/reports/1211160
PR-URL: https://github.com/nodejs-private/node-private/pull/269


Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>