gateway: orderservice-resolver that will call order-service client

[pooranjoyb]

The Workflow should look like this:

GraphQL Mutation: User calls createOrder/getOrder/updateOrder/deleteOrder.

Gateway Resolver: Receives the request and sends a POST request via HTTP to the Order Service.

Order Service: Saves the order to PostgreSQL and publishes an event to RabbitMQ.

Gateway Resolver: Receives the confirmation from the Order Service and returns the Order object to the client.