A Gutenblock for the Contact Form.

[georgestephanis]

The results of a sick George:

At this point it just represents the parent form -- it doesn't handle any fields yet.

That will largely depend on how WordPress/gutenberg#3745 progresses.

Kinda treating this as a weekend-only passion project as time is available. If anyone wants to own it and chase it down, feel free to take it over.

== Design Decisions ==

• Form-specific settings such as Subject and To should be tucked away into the Block Inspector.
• The contents of the form (fields and such) will be handled as nested blocks, and leverage core Gutenberg functionality to do such. This will also allow for adding of some core block types inside a form for aesthetics (new bonus benefit)

[stale]

This PR has been marked as stale. This happened because:

• It has been inactive in the past 3 months.
• It hasn’t been labeled `[Pri] Blocker`, `[Pri] High`.

No further action is needed. But it's worth checking if this PR has clear testing instructions, is it up to date with master, and it is still valid. Feel free to close this issue if you think it's not valid anymore — if you do, please add a brief explanation.