Provide better privacy guidance

[maxime-rainville]

Problem

User forms make it easy to create forms. The problem is that a lot of content authors won't have a good understanding of

• the privacy implications of creating a new forms
• privacy best practices
• their legal obligations under the NZ Privacy Act or EU's GDPR or other relevant legislation
• data retention policy.

While we currently outsource all those thorny questions to web agencies and content authors, we could still make an effort to better highlight those problems to content authors.

User story

As a content author, I want privacy guidance when using user forms so I can meet my ethical obligations.

[maxime-rainville]

On the data retention point, there's probably some extra option we could implement like auto deleting submission after X number of days.

[lerni]

For clean-up Baukes module works great: https://github.com/hamaka/userforms-cleanupsubmissions
In my setup I also add automatically a linked "Terms & Condition" checkbox, but this obviously differs from setup to setup.