Create a macOS specific a11y debugging API

Create a (probably, temporary) accessibility related debugging API that will dump both accessibility hierarchy with native and JXF components representation, current state and also track the correlation between native accessibility peers and the JFX components and their integral parts.

The reason this API is required is that during the debug session when breakpoint happens the focus is shifted and the voiceover context can be lost so ability to do a snapshot of the context is very desirable.