Utilities/Release: Add script to sign/notarize macOS application bundle

Brad Kingrequested to merge
brad.king/cmake:rel-macos-sign-notarize into master

We produce macOS binaries for cmake.org using GitLab CI jobs. Binaries for official releases are additionally signed and notarized manually by a maintainer with suitable signing certificates and Apple developer account credentials. Add a script to drive these steps.

Backport: release:HEAD~1^2

Merge request reports