Generic dlt + GraphQL factory

[ryscheng]

What is it?

Some GraphQL APIs support schema introspection
https://graphql.org/learn/introspection/

This is something the developer has to turn on (we do for our API).
If it exists, then we can programmatically crawl the schema to determine everything we want to grab from a GraphQL API.

If we had this kind of factory, it would make it trivial to replicate any GraphQL API that support introspection.

[ryscheng]

Idea from @Jabolol we should make the configurations sufficiently expressive to limit complexity.
e.g. limit the depth of a query

[ryscheng]

Might be nice to specify a GraphQL fragment if there's only a specific thing that we want (e.g. from the GitHub API)