Project structure refactor:

- Change package name general_server to gateway
- Changing the structure of directories and packages
- Adding vendor to the project

vendor/github.com/go-viper/mapstructure/v2/reflect_go1_20.go

@@ -0,0 +1,10 @@
+//go:build go1.20
+
+package mapstructure
+
+import "reflect"
+
+// TODO: remove once we drop support for Go <1.20
+func isComparable(v reflect.Value) bool {
+	return v.Comparable()
+}