JWT Token Management for Harvester Authentication

[wibarre]

Current State: Galadriel Server utilizes an in-memory Key Management System (KMS) for generating keys to sign JWT tokens. This is currently a proof-of-concept (POC) level implementation that lacks support for key rotation.

Proposed Enhancements:

• Investigate the feasibility of integrating with external KMS services like AWS KMS, particularly with an eye toward enhanced security features such as key rotation.
• Explore the possibility of leveraging external OAuth2/OpenID providers for JWT token.