fix: use of generic oauth provider (#5345)

Adds a id_attribute to the GenericOAuthProvider, which is used to map the external User. Further mapping can be done in actions by using the `rawInfo` of the new `ctx.v1.providerInfo` field.

internal/command/idp.go

@@ -16,6 +16,7 @@ type GenericOAuthProvider struct {
 	TokenEndpoint         string
 	UserEndpoint          string
 	Scopes                []string
+	IDAttribute           string
 	IDPOptions            idp.Options
 }