Change OSX CD to build a universal binary

[dmalec]

This MR follows up on #186 to address the CD build for versions of OSX prior to 11. CD now builds two version of wxWidgets and two versions of Logo for OSX, using matrix builds to target x86 and ARM. It then adds a stage which takes the individual platform builds of OSX Logo and combines them into a universal binary build.

Caveats

Size - this does result in a larger application file; I think there may be value in checking what can be disabled in the wxWidgets build without impacting the parts of wxWidgets used by UCB Logo.

Duplicate build logic - I'd like to not replicate the portion of the Makefile which builds the DMG into the CD file; but, I ran into some challenges in solving that and would like to mull some more. My thinking is that, in the meantime, this change will restore CD to working for the platforms it was previously working for. Understood if folks would like to hold off until the two places can be unified appropriately.

Testing

Downloaded the universal binary produced by the CD pipeline and was able to run it on both platforms. Checked via command line that OSX sees this as a universal binary:

file /Volumes/UCBLogo/UCBLogo.app/Contents/MacOS/UCBLogo 
/Volumes/UCBLogo/UCBLogo.app/Contents/MacOS/UCBLogo: Mach-O universal binary with 2 architectures: [x86_64:Mach-O 64-bit executable x86_64] [arm64]
/Volumes/UCBLogo/UCBLogo.app/Contents/MacOS/UCBLogo (for architecture x86_64):	Mach-O 64-bit executable x86_64
/Volumes/UCBLogo/UCBLogo.app/Contents/MacOS/UCBLogo (for architecture arm64):	Mach-O 64-bit executable arm64

Test Environments

• OSX Catalina (10.15.7) running on Intel Core i7
• OSX Ventura (13.6.6) running on Apple M2

[jrincayc]

Reviewed and approve.