[HTML Examples] Image and multimedia ~ audio

[schalkneethling]

Need an HTML example for the audio element
https://developer.mozilla.org/en-US/docs/Web/HTML/Element/audio

Contributing

https://github.com/mdn/interactive-examples/blob/master/CONTRIBUTING-HTML.md

[Elchi3]

I think this was already done in #627

[wbamberg]

Yeah, this was done, but I just threw something together for user testing. It's worth someone taking a look to see if they can improve it, I think.

[stephanmax]

Would you mind me taking a look?

[wbamberg]

@stephanmax , I would not mind at all!