Next iteration of fetch_data connectors concept

[anthony-chaudhary]

Current Issues

While working on #1523 there were a few challenges:

• The return type of objections using the connector pattern felt brittle and hard to update.
  1d4da2b
  Prior used the unclear string result which created bad coupling and assumptions. For example for error checking, is result expected to always be present or not?

• Error handling and passing of objects generally was hard to think about. It would seem like sometimes we would be doing similar error checking in multiple places.

• It was hard to follow code becuase fetch data uses string to test the approach.