* Authn: Resolve authenticate by and auth id when fethcing signed in user
* Change logout client interface to only take Requester interface
* Session: Fetch external auth info when authenticating sessions
* Use authenticated by from identity
* Move call to get auth-info into session client and use GetAuthenticatedBy in various places
* AuthN: Move identity struct to its own file
* IDForwarding: Add IDToken property to usr and identity structs and add GetIDToken to requester interface
* Inject IDService into background services
* IDForwarding: Register post auth hook when feature toggle is enabled
Karl Persson