A Person may have multiple associated PersonIdentities.  The object
relation link between these data structures was previously introduced
as "person", but is renamed "identities" with this patch.

This changes the access pattern from:

	person.person.all() -> QuerySet[PersonIdentity]

To:

	person.identities.all() -> QuerySet[PersonIdentity]

Fixes: GREG-20

Fixes: GREG-20

Mostly a visual improvement, but instead of importing the entire
django_filters.rest_framework module we make the dependency situation
clearer by importing specific symbols.

Fixes: GREG-20

The list(self, request, *args, **kwargs) function drops args and kwargs
by not passing them on to the super class.

Fixes: GREG-20

GREG-17: Adding constraint to avoid duplicate roles

See merge request !23

Add sponsor guest endpoint

See merge request !20

GREG-10: Adding cascading deletes for persons

See merge request !19

GREG-7: Simple task running functionality. Adding ask for checking roles about to expire

See merge request !18

GREG-6: Notifications for person related changes

See merge request !16

GREG-5: Adding methods for updating and deleting role for person

See merge request !15

GREG-5: Adding handling of listing and creating identities for persons

See merge request !13

Updates to datamodel

See merge request !17