Updates to PD registration flow

[jimchamp]

Makes the following changes to the PD flow when a patron first logs in:

• unqualifed pda values are captured on the account
• pda and rpd values are written to the account before the email is sent
• Adds a new rpd status code (this may require discussion), and encodes these as an Enum

New login flow:

1. Patron with pda cookie logs in.
2. The pda value is added to the patron's account
3. rpd is added to the account, with a value of 0 (signifying that they are requesting special access).
4. "Next steps" email is sent to patron.
5. Account's rpd value is updated to 1 (meaning that the email has been sent).
6. pda cookie is unset and expired.

Technical

Testing

Screenshot

Stakeholders