Refactor Exo Rego Code

[Sloane4]

🗣 Description

The rego code has been expanded greatly, but: with the addition of Regal (OPA linter), update is style practices, & increase in duplicate code, there is a need for a "clean up".

💭 Motivation and context

• Not triggering any linter warnings/errors (i.e. line length, some in, identical test names, constant conditions, wildcard & test outside test package)
• Style uniformity with booleans (i.e. == true, == false, not ExampleMethod(), ExampleMethod() == true, and Method() := true if {}
• Match util import to file structure import data.report.utils.NotCheckedDetails -> import data.utils.report.NotCheckedDetails
• Refactor out a general ReportsUtil functions for file to be added to Report Utils file in separate PR
• Simplify code as much as possible by reducing duplicate code
  Closing Refactor EXO Rego Code #635

🧪 Testing

• Unit Tests

✅ Pre-approval checklist

• This PR has an informative and human-readable title.
• Changes are limited to a single goal - eschew scope creep!
• All future TODOs are captured in issues, which are referenced
  in code comments.
• All relevant type-of-change labels have been added.
• I have read the CONTRIBUTING document.
• These code changes follow cisagov code standards.
• All relevant repo and/or project documentation has been updated
  to reflect the changes in this PR.
• Tests have been added and/or modified to cover the changes in this PR.
• All new and existing tests pass.

✅ Pre-merge checklist

• Revert dependencies to default branches.
• Finalize version.

✅ Post-merge checklist

• Create a release.

[schrolla]

One minor comment for resolution.

[crutchfield]

Some of the same general comments apply that were made on other refactored rego. But it is so much better looking than before.

[Sloane4]

@nanda-katikaneni ready for merge