Confirm IPR disclosure submitter's email address

[rjsparks]

When an anonymous user posts an IPR disclosure using an address unknown to the datatracker, put the disclosure in a new unconfirmed state, and send email to the submitter's address with a link to confirm the submission. When the link is followed, move the disclosure into the existing "pending" state, and offer the user following the link the opportunity to create a datatracker account.

If the anonymous user provides an address already known to the datatracker as the submitter, ask that they log in to proceed instead.

The workflow for people already signed into the datatracker should not change.