xcframework : add support for CoreML to ios/macOS (#2912)

xcframework : add support for CoreML to ios/macOS (#2912)

* xcframework : add support for CoreML to ios/macOS

This commit add support for compiling whisper with CoreML support for
iOS and macOS.

The motivation for this change is it will allow users to use a Core ML
model or fall back to a ggml model if Core ML is not available.

With the updated xcframework, I was able to run the whisper.objc example
and successfully load a Core ML model:
```console
whisper_init_state: loading Core ML model from '/Users/danbev/Library/Developer/CoreSimulator/Devices/25E8C27D-0253-4281-AF17-C3F2A4D1D8F4/data/Containers/Bundle/Application/B81F6FF0-BF1A-40DF-AC2A-3908EC4BCC9A/whisper.objc.app/ggml-base.en-encoder.mlmodelc'
whisper_init_state: first run on a device may take a while ...
whisper_init_state: Core ML model loaded
```

* squash! xcframework : add support for CoreML to ios/macOS

Fix grammar in output message.