Support for AARC-G052 guideline "Proxied Token Introspection"

[enricovianello]

This specification extends the OAuth 2.0 Token Introspection method defined in RFC 7662. It defines a method for an OAuth 2.0 Authorization Server (AS) that receives an introspection request for a token it did not issue, to query a different, trusted AS. This enables the AS to determine the active state of the token and to retrieve associated metadata.

Source: https://aarc-community.org/guidelines/aarc-g052/