AMOENG-2401 - support form in devhub

[bakulf]

Fixes AMOENG-2401

Description

This commit introduces a support form in devhub.

Checklist

• Add #ISSUENUM at the top of your PR to an existing open issue in the mozilla/addons repository.
• Successfully verified the change locally.
• The change is covered by automated tests, or otherwise indicated why doing so is unnecessary/impossible.
• Add before and after screenshots (Only for changes that impact the UI).
• Add or update relevant docs reflecting the changes made.

[diox]

• we typically add a migration for the waffle switch in the db so that it's already there when we need to turn it on.

[ioanarusiczki]

@bakulf This has been enabled on dev, I enabled it for stage.
In the screenshot above there's a Related add-on field -> this I didn't see being displayed
The form sends some information somewhere because I am getting a successful message after submitting it.
All fields are mandatory.

[bakulf]

We decided to remove the add-on field because it requires more thinking. And yes, now the form is what you are seeing.