feat(oidc): token exchange impersonation (#7516)

* add token exchange feature flag

* allow setting reason and actor to access tokens

* impersonation

* set token types and scopes in response

* upgrade oidc to working draft state

* fix tests

* audience and scope validation

* id toke and jwt as input

* return id tokens

* add grant type  token exchange to app config

* add integration tests

* check and deny actors in api calls

* fix instance setting tests by triggering projection on write and cleanup

* insert sleep statements again

* solve linting issues

* add translations

* pin oidc v3.15.0

* resolve comments, add event translation

* fix refreshtoken test

* use ValidateAuthReqScopes from oidc

* apparently the linter can't make up its mind

* persist actor thru refresh tokens and check in tests

* remove unneeded triggers

internal/api/oidc/key.go

@@ -311,7 +311,7 @@ func (o *OPStorage) SigningKey(ctx context.Context) (key op.SigningKey, err erro
 			return err
 		}
 		if key == nil {
-			return zerrors.ThrowInternal(nil, "test", "test")
+			return zerrors.ThrowNotFound(nil, "OIDC-ve4Qu", "Errors.Internal")
 		}
 		return nil
 	})