MacOS certificates and notarization

[jsbrittain]

Add MacOS certificates and notarization to publishing workflows.

Certificates are stored as github repository secrets in accordance with these guides:

• https://docs.github.com/en/actions/deployment/deploying-xcode-applications/installing-an-apple-certificate-on-macos-runners-for-xcode-development
• https://federicoterzi.com/blog/automatic-code-signing-and-notarization-for-macos-apps-using-github-actions/

Nightly publishing action has been tested on the forked repo here (see note about Windows build, below):

• action: https://github.com/jsbrittain/GRAPEVNE/actions/runs/8551807836
• release: https://github.com/jsbrittain/GRAPEVNE/releases/tag/nightly

Publishing workflow has been tested on the forked repo here (see note about Windows build, below):

• action: https://github.com/jsbrittain/GRAPEVNE/actions/runs/8553033715
• release: https://github.com/jsbrittain/GRAPEVNE/releases/tag/untagged-e9e60b95039652a5287a

Note: We use fail-fast: false in these actions due to a sporadic 'upload' issue which afflicts the Windows build (the build itself is stable). This is the subject of a separate PR #130 .

The build.yaml file is used for testing purposes only.

Commits will be squash merged.

Resolves #123