Remove id autogeneration from db models

Remove automatic uuid v4 ID generation from the models and replace it
with `shared.NewId()`, which generates an Id depending on the config
setting

storage-new/self.go

@@ -129,6 +129,7 @@ func insertUser(
 		)
 	}
 	user := models.User{
+		ID:                   shared.NewId(),
 		Username:             shared.ServerActorName,
 		Server:               *server,
 		ServerId:             server.ID,