chore: add optional title, width, height attrs to YouTube embed

[bsmth]

Summary

This PR adds a few more parameters to the YouTube embed macro.

Problem

Currently the title, width and height are hardcoded, so it would be nice to be able to customize these.

Solution

Add three optional parameters that fall back to current hardcoded values if not given.

Screenshots

How did you test this change?

{{EmbedYouTube("hs3piaN4b5I", "Awesome Flexbox video", 200, 100)}}

yarn && yarn dev