Add graphql api creation by SDL url and introspection

[nisan-abeywickrama]

Purpose

This feature enhances the GraphQL API creation capabilities by adding support for additional methods: creating APIs using an SDL URL and using the introspection method by providing an endpoint.

Implementation

• Update validateGraphQLSchema rest api to support url and useIntrospection
• Update import graphql schema to support using url or introspection
• Add new exceptions codes for this feature
• Create function to retrieve schema from sdl url.
• Create function to retrieve schema from introspection query to the given endpoint