Implement notifications service with shared messaging and email drivers (#36)

backend/shared/messaging/config.go

@@ -0,0 +1,13 @@
+package messaging
+
+import "git.sendico.io/tech/sxchnge/shared/model"
+
+type BrokerBus string
+
+const (
+	BBNats BrokerBus = "NATS"
+)
+
+type (
+	Config = model.DriverConfig[BrokerBus]
+)