Migration to API client resource gateway

The resource gateway functionality has been updated to use a API client instead of a Web client. For web clients the Token validation functionality is deprecated, but still supported. Instead, an API client with the Token introspection scope should be used. Configuration is described in configuring a resource gateway as API client

Not only the way how a resource gateway should be configured is changed. Also how it should be implemented. The Token introspection rfc7662 should be used. In the old situation this was the token validation endpoint as described in the oauth api reference. For the new api see the token introspection api reference guide