[Demo app] Add audio transcription example; add image generation example

[DJBen]

Is your feature request related to a problem? Please describe. The demo app includes a chat example; audio and image generation remains TBD.

Describe the solution you'd like Using the OpenAI API, add audio transcribe and image generation demos.

Describe alternatives you've considered Not doing them.

[DJBen]

Would be nice if you can tag this as "help wanted"

[Krivoblotsky]

Sure. Done ✅

[SunburstEnzo]

I've added an Image Generation example to the demo – let me know if there's anything you'd like changed in it 😊 I think it could definitely be improved to show the images rather than just list the URLs but didn't know what would be best to load those images (if we need a cache, etc – worth using something like SDWebImage?)