Documentation for Server to Server (S2S) Authorization

Issue Description

• The issue is to do a reading on how server-to-server authorization works, how microservices work, how services identify each other, and create documentation on s2s auth.

Expected Behavior

• The document should explain how server-to-server auth works and how it can be implemented for the requirement discussed.

Additional Information

• The requirement is to implement this server-to-server authorization on a portal which will act as a dashboard in RDS to rotate the keys and key management.

Checklist

• I have read and followed the project's code of conduct.
• I have searched for similar issues before creating this one.
• I have provided all the necessary information to understand and reproduce the issue.
• I am willing to contribute to the resolution of this issue.
• I have finished the documentation post reading

Start with the S2S authorization, microservices, service-identity, portal, and RDS key-rotation requirements stated in the issue; no files or tests are named. Define the documentation's implementation guidance and key-management scope, then verify it explains how services authenticate and how the proposed portal requirement is addressed.