feat: add libraries flag to MacConfig (1.x)

[dongcarl]

For macOS apps leveraging SMAppService, we need to place a codesigned plist under the app's Contents/Library/LaunchDaemons directory. This is outside of the Contents/Resources directory so we can't use the resources flag.

The PR as it stands adds a libraries flag to MacConfig to allow this

[FabianLars]

Thanks for contributing! We recently merged a similar PR into dev (v2) here #7798 and i think it'd make more sense to backport this / match its name and behavior :)
( -> i'm not sure that a simple git cherry pick would be easy so i would be fine if it's recreated instead 🤷 )

Also, we require all commits to be signed to merge a PR. Here's a guide for that: https://docs.github.com/en/authentication/managing-commit-signature-verification/about-commit-signature-verification#ssh-commit-signature-verification - i recommend the ssh approach because i think it's easier but a guide for gpg is right above that though.