Set claim from token on Django user model

[tschale]

We should enable pycloak to set claims from the token on the Django user model.

Let's take following example:

• claim birthday
• User model has a UserProfile, which has the field birth_day, i.e. user.profile.birth_day

We need a setting PYCLOAK_CLAIM_TO_USER_MAPPING, which maps the name of the claim to the field of the user. This needs to support nested related lookups, separated by dot-notation. Optionally a callback function can be specified, if the value needs parsing/processing.

Example:

from wherever import parse_birthday

PYCLOAK_CLAIM_TO_USER_MAPPING = {
    "birthday": {"field": "profile.birth_day", "callback": parse_birthday
}

We need a setting PYCLOAK_CLAIM_SKIP_MISSING. If this is True, pycloak skips when the claim is not present in the token and logs a warning. If this is False, pycloak will raise a django.core.exceptions.ImproperlyConfigured error.

We need a setting PYCLOAK_CLAIM_IGNORE_VALIDATION_ERRORS. If this is True, pycloak logs a warning when a validation error is raised. If this is False, pycloak will raise the exception.

The field on the user model is set in the middleware at 7. login user. We only need to set it, if we login the user or if it's the same user with a new token.