Add ability to search verified second factors by ID.
Deserialise verified second factor registration code.
Add ability to list RAs.
Add ability to search for unverified second factors by nonce.
Fix verified second factor deserialisation test.
Merge pull request #13 from SURFnet/feature/display-code-list-ras

Add features needed for displaying the registration code and a list of RAs on screen in the Self-Service.