Update docs with configuration instructions for Defender

[james-garriss]

💡 Summary

The configuration pages (/docs/configuration/configuration.md) has configuration instructions for specific products. While there are instructions for Entra ID, the instructions for Defender are a placeholder (see the heading Defender Configuration). The placeholder should be replaced with the actual instructions.

Motivation and context

These optional configuration instructions enable admins to create exclusions. Without instructions, however, admins are unable to take advantage of these features for Defender.

Implementation notes

Please provide details for implementation, such as:

• Add instructions (update docs)
• Test instructions

Acceptance criteria

• [ ] Admins understand how to configure exclusions for Defender.

[schrolla]

May also want to update Defender report to point to configuration documentation similar to updates to AAD.