move gotd fork into repo. (#111)

- update to latest telegram layer
- remove some references to fields in tg.Entities that don't exist in
the schema
- originally added here:
https://github.com/beeper/td/commit/820929062a2ba0104397bc01235ab58a9cff780e
  - referenced here
-
https://github.com/mautrix/telegramgo/commit/124f0967ed195b5a380c9bd02e170ada9710dde3
-
https://github.com/mautrix/telegramgo/commit/4205047aab2e0639217148b5d125bfaab668bd8e

pkg/gotd/gen/args.go

@@ -0,0 +1,19 @@
+package gen
+
+type structConfig struct {
+	Struct structDef
+	Config config
+}
+
+func newStructConfig(s structDef, c config) *structConfig {
+	return &structConfig{Struct: s, Config: c}
+}
+
+type interfaceConfig struct {
+	Interface interfaceDef
+	Config    config
+}
+
+func newInterfaceConfig(i interfaceDef, c config) *interfaceConfig {
+	return &interfaceConfig{Interface: i, Config: c}
+}