Add support for 3rd Party Mac Developer Installer certificates

[ky1vstar]

This PR add productbuild tool to trusted app list when certificates are imported. productbuild is used to generate .pkg to be uploaded to TestFlight for macOS.

[daveisfera]

I'm not familiar with this. Can you help me understand what it does and why it's needed?

[ky1vstar]

@daveisfera so, *.ipa files is what you upload to App Store Connect in order to distribute your app. IPA is required to be signed beforehand using codesign util with Distribution certficate.
If you want to distribute an macOS app, you would need to upload *.pkg which is Apple's package installer format. This PKG is required to be signed with Mac Installer certificate using productbuild util.