Add a step to display a form and collect information

[andergmartins]

This could be used in conjunction with the idea #1239, allowing the collection of information and continuing the workflow.

The data is available in the execution context, but can also be optionally stored. It could be stored by default as a custom post type, but also could be adjusted to be stored as post/user/site meta.

It can also be used with the conditional step to custom the flow direction in the workflow.
Having an option to require login and specific permission is important.

One think we need to think a little more is how to display the form. Always in a frontend page?
Allow displaying it also in the backend in a JS modal?

Add an option to generate a link for it? Or should we merge this idea with the #1239?

Should this be split into different steps? Confirmation, Question, custom form?

The name could be something like: Wait for user interaction.