Code for guest routes moved to their own folder so that we don't need
multiple api calls.
Serializer class for roles has been simplified with methods for
validation of each field and a separate one used in invites without
requiring the person field.

Resolves: GREG-61

Remove the 'email' and 'mobile_phone' fields on Person and use identities to represent this data instead.

- Migrate data on existing Person objects to Identity objects
- Make the 'is verified' logic only accept certain ID types
- Sync the Person.is_verified and API 'verified' filter logic