[#2762] added Yandex OAuth2 provider

Co-authored-by: Valentine <xb2w1z@gmail.com>

tools/auth/auth.go

@@ -133,6 +133,8 @@ func NewProviderByName(name string) (Provider, error) {
 		return NewInstagramProvider(), nil
 	case NameVK:
 		return NewVKProvider(), nil
+	case NameYandex:
+		return NewYandexProvider(), nil
 	default:
 		return nil, errors.New("Missing provider " + name)
 	}