Add Documentation for MacOS CoreML Builds

### Describe the documentation issue

The current page only contains information about how to build with the CoreML provider for iOS.
It's also not apparent if the osx builds contain the coreml execution provider.

### Page / URL

https://onnxruntime.ai/docs/execution-providers/CoreML-ExecutionProvider.html#build

Start with the CoreML Execution Provider page at the linked URL, especially its Build section. Check the project’s macOS build documentation or configuration to determine whether macOS builds include the CoreML execution provider. The documentation is done when it explains how to build for macOS and clearly states whether those builds contain CoreML support.

Written by the indexing model from the issue text.