Implement GraphQL based import source

[lazyfrosch]

This allows users to query data from various GraphQL APIs.

https://moonhighway.com/public-graphql-apis

Example

URL: https://swapi-graphql.netlify.app/.netlify/functions/index
Key Column: name
Query:
  query {
    allPeople {
      people {
        name
        birthYear
        hairColor
        species {
          name
        }
        homeworld { 
          name
        }
      }
    }
  }
Extract Property: data.allPeople.people

TODO

• Documentation
• Auto-detect property to extract?