Move admin views for users, groups, and object permissions from the admin site to the NetBox frontend
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Co-authored-by: Jeremy Stretch <jstretch@netboxlabs.com>
* 12794 change User ref to get_user_model
* 12794 call get_user_model once in tests
* 12794 call get_user_model once in tests
* 12794 use settings.AUTH_USER_MODEL for FK reference