feat(login): use default org for login without provided org context (#6625)

* start feature flags

* base feature events on domain const

* setup default features

* allow setting feature in system api

* allow setting feature in admin api

* set settings in login based on feature

* fix rebasing

* unit tests

* i18n

* update policy after domain discovery

* some changes from review

* check feature and value type

* check feature and value type

internal/config/hook/feature.go

@@ -0,0 +1,27 @@
+package hook
+
+import (
+	"reflect"
+
+	"github.com/mitchellh/mapstructure"
+
+	"github.com/zitadel/zitadel/internal/domain"
+)
+
+func StringToFeatureHookFunc() mapstructure.DecodeHookFuncType {
+	return func(
+		f reflect.Type,
+		t reflect.Type,
+		data interface{},
+	) (interface{}, error) {
+		if f.Kind() != reflect.String {
+			return data, nil
+		}
+
+		if t != reflect.TypeOf(domain.FeatureUnspecified) {
+			return data, nil
+		}
+
+		return domain.FeatureString(data.(string))
+	}
+}