NXP-12981: Use Nuxeo signing identity delivered by Apple
NXP-12981: Update code signing doc for Windows about use of a trusted certificate
NXP-12981: Update code signing doc for OS X about use of a trusted certificate
Set default environment variables if not set
Merge branch 'master' of https://github.com/nuxeo/nuxeo-drive
Remove useless empty README.rst
NXP-12981: Add PFX certificate password option when signing msi