docs: Add ADR for module status metrics

[chrkl]

Description

Changes proposed in this pull request (what was done and why):

• Add ADR for module status metrics

Changes refer to particular issues, PRs or documents:

• Concept on how to collect module status metrics #921

Traceability

• The PR is linked to a GitHub issue.
• New features have a milestone set.
• New features have defined acceptance criteria in a corresponding GitHub Issue, and all criteria are satisfied with this PR.
• The corresponding GitHub issue has a respective area and kind label.
• The follow-up issues (if any) are linked in the Related Issues section.
• Adjusted the documentation if the change is user-facing.
• The feature is unit-tested
• The feature is e2e-tested

[kyma-bot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[NHingerl]

I'd put this section (line 69-73) before the example of line 57-67.

[chrkl]

Done