[1360] New user role: Evaluator

[cpreisinger]

Description

Adds evaluator role and related functions and tests

Related Issues

1360

1390 - May eventually add to this PR

Changes Made

• Add evaluator role
• Add evaluator checking functions
• Add tests
• Update and add tests

Checklist

• [x] PR is assigned to a project: Challenge_gov Board
• [x] PR is assigned to a milestone: current sprint
• [x] GH issues are assigned to the PR (under Development section on the right hand side)
• [x] PR is assigned a reviewer, and requires code review and approval by a teammate
• [x] New functionality is tested and all tests are green
• [x] I have added unit tests for new functionality or updated existing tests for changes.
• [x] I have updated the documentation/README accordingly, if necessary.
• [x] If you have DB migration, it is a "safe" migration and you've confirmed it can be rolled back.
• [x] If applicable, Controllers modified contain appropriate authorization plugs
• [x] This PR has been reviewed by at least one other team member.