v3.1.11 macOS cleanup

#457 - Wavemode 7 support
#461 - 80% of the way there for Apple Silicon M1 support (almost able to build universal binaries. https://discourse.libsdl.org/t/compile-macos-universal/28759)
macOS installer now a single installer for both SDL app and Music.app plugin
#462 - fix shader compilation with GLSL 330

Mac build should now be code signed. Please file an issue if you get have any issues running it.