Add Defender configuration options documentation

[schrolla]

🗣 Description

Expands the existing Defender Configuration section in the docs/configuration.md documentation file to explain the existing Defender policy-specific configuration file options, what they represent, and how to use them.

💭 Motivation and context

Closes #1134

🧪 Testing

This is a documentation only update. The testing is to manually review the updated documentation for grammar, spelling, and clarity.
Additional testing would include running ScubaGear with the example Defender configuration file referenced in the documentation, adjusting the various policy-specific variables referenced in the documentation to confirm what is said in the docs matches the expected operation in ScubaGear.
Note this update includes converting config page absolute links to relative links when referencing sections in the same document or sample configuration files in the repo. Confirm links are not broken.

✅ Pre-approval checklist

• This PR has an informative and human-readable title.
• PR targets the correct parent branch (e.g., main or release-name) for merge.
• Changes are limited to a single goal - eschew scope creep!
• Changes are sized such that they do not touch excessive number of files.
• All future TODOs are captured in issues, which are referenced in code comments.
• These code changes follow the ScubaGear content style guide.
• Related issues these changes resolve are linked preferably via closing keywords.
• All relevant type-of-change labels added.
• All relevant project fields are set.
• All relevant repo and/or project documentation updated to reflect these changes.
• Unit tests added/updated to cover PowerShell and Rego changes.
• Functional tests added/updated to cover PowerShell and Rego changes.
• All relevant functional tests passed.
• All automated checks (e.g., linting, static analysis, unit/smoke tests) passed.

✅ Pre-merge checklist

• PR passed smoke test check.

• Feature branch has been rebased against changes from parent branch, as needed

  Use Rebase branch button below or use this reference to rebase from the command line.

• Resolved all merge conflicts on branch

• Notified merge coordinator that PR is ready for merge via comment mention

• [ ] Demonstrate changes to the team for questions and comments.
  (Note: Only required for issues of size Medium or larger)

✅ Post-merge checklist

• Feature branch deleted after merge to clean up repository.
• Verified that all checks pass on parent branch (e.g., main or release-name) after merge.

[james-garriss]

This link doesn't go anywhere:

The sample configuration file also uses Anchors and Aliases...

[james-garriss]

This link doesn't go anywhere:

See the sample configuration file shown in the previous section Defender Configuration...

[james-garriss]

Changes sound good.

[schrolla]

This link doesn't go anywhere:

The sample configuration file also uses Anchors and Aliases...

Good catch. Should have used dashes in place of spaces, not removed them to make the valid link. Fixed in 5587a3d

[schrolla]

This link doesn't go anywhere:

See the sample configuration file shown in the previous section Defender Configuration...

Good catch. Should have used dashes in place of spaces, not removed them to make the valid link. Fixed in 5587a3d

[nanda-katikaneni]

Used the updated documentation to create a new config file with Defender policy specific variables. Worked good and documentation is helpful. Approved.

[schrolla]

@nanda-katikaneni Smoke test passed, PR has been approved and rebase. Ready for merge.