`AwaitingControllerNotice` should be split into steps

[zner0L]

The content of the AwaitingControllerNotice step is really confusing. Especially adding the attachments is an easy but problematic oversight. I propose presenting the step as a series of substeps, which we ask the user to confirm. Like this:

1. Create email [x]
2. Attach files [ ]
3. Copy email content [ ]
4. Send and upload [ ]

I also think that we should provide or link to an explanation how to export the PDF from a mail client, especially since we do not provide the email sink mailbox right now.