Remove CodeQL reusable workflow

[ArchonVII]

Problem
CodeQL is present as an active reusable workflow and advertised example in github-workflows, but ArchonVII does not use CodeQL.

Goal
Remove the reusable CodeQL workflow and example caller so new consumers are not pointed at the service.

Acceptance Criteria

• Delete the reusable CodeQL workflow.
• Delete the CodeQL example caller.
• Remove CodeQL from the workflow catalog/docs in this repo.
• Verify the remaining workflow catalog/tests still pass.