Added kernos_api_keys configuration variable to enable optional
request authentication via Bearer or X-Api-Key headers. Updated
Kernos documentation with setup instructions and usage examples.
Also corrected FastAPI project port assignments in Ouranos docs.
Replaces the minimal project description with a comprehensive README
including a component overview table, quick start instructions, common
Ansible operations, and links to detailed documentation. Aligns with
Red Panda Approval™ standards.
