Convert REST API server to BFF component

The BFF component will be a bridge between UI and different backend microservices

1. Remove REST API endpoint, keep GraphQL endpoint.
2. Remove database, ORM, and repository layers, all the data will come from other microservice components
3. Remove Spring security authentication and authorization: the API gateway will do the authentication and micro service components will handle authorization. 
4. UI will download GraphQL schema, generate UI types and retrieve data using GraphQL