Editor: Launch contact form to production

[rralian]

Before we do this though, I wonder if this should take into account our planned UX for adding a widget/app/embed into a post/page (#4682). If we plan to change how/where the contact form is added to a page, it may be worth waiting for that design spike to implement it, rather than launching this briefly and then changing where it lives.

/cc @rodrigoi @adambbecker @drw158

[davewhitley]

The icon will probably be moved once we actually implement widgets. That is far off though, and I think we need to launch the contact form before then. It won't be drastically different — it will probably still live in the tiny MCE area.

[rralian]

sounds good

[mtias]

See #4545.