(make-pipeline-a-solid-2) container_definition --> graph_definition
Summary:
Rename container_definition to graph_definition and make it required
in Solid.
Depends on D4847
Test Plan: BK
Reviewers: alangenfeld, max, dgibson, sandyryza
Reviewed By: sandyryza
Differential Revision: https://dagster.phacility.com/D4882