Build OAuth Support

IO ingresses support OAuth authentication. Client configuration is provided in host blocks, and IO intercepts all OAuth-related paths to handle signin and token management. Instead of passing tokens directly to backends, IO provides a session token that backends can send with their Calling Mode requests and IO will automatically apply the appropriate authorization token. Pros This offloads a tedious and common challenge for application developers. OAuth can be used by backend applications in any language. Cons Configuration is a bit complex and currently is only supported in HCL.