Updated framework dependencies and build to emit universal binaries

[jimcheng256]

Apple Silicon users have been receiving deprecation warnings because the existing Atlantis 0.9.9.8 is x86_64-only. While they should still be able to run existing Atlantis builds until macOS 28, when Rosetta 2 is sunset, we'll need to update the codebase to produce universal binaries to avoid these warnings and ensure that Atlantis remains usable for years to come.

This changeset contains updates to allow us to build universal binaries for both x86_64 and arm64, Namely:

• Updated Sparkle.framework to 2.9.3.
• Updated OgreKit.framework to 2.1.12 (NB: this is now retired by its maintainer)
• Removed Growl.framework (ancient, abandoned, and does not support arm64).
• Commented out references to Growl for the time being (will need to port these to native notifications).
• Removed deprecated VALID_ARCHS key from the project to allow default universal binary builds.