Wbprice/ndh 812 load tester user migration

[wbprice]

module-name: Create load tester user

Jira Ticket # NDH-812

Problem

We want to create a load testing user for automated and ad-hoc manual tests. This user must be registered with Django to accept authenticated requests.

Solution

Adapt earlier work on creating a super user in django to create a regular user (not staff!) for load testing

Result

New user for load testing with limited permissions is created

Test Plan

This works in conjunction with NDH-812 PR in the npd-ops repo. To test locally, set the load test user param:

NPD_LOAD_TESTER_PASSWORD='pbkdf2_sha256$1000000$c363cb9f32102ece1abd4ab15c4312e8$w+uGYI4KnRgwsFC9sA2BlqETdntjQiO/jAtn9+lGbOs='

that hash corresponds to testpassword
so try to login at localhost:8000 (not the admin dashboard) with the creds:

npd+load+tester@cms.hhs.gov
testpassword