#1 Document ingestion endpoint

There are 4 approaches to do this: 1. Accept a POST request at /graphql endpoint with an input object containing the url where xml is available. 2. Accept a POST request at /graphql endpoint with the input object containing the body of the xml document. 3. Accept a POST request at /ingestDoc with the xml document in the request body. 4. Accept a GET/POST request with the url of the xml document in query/request body.