[schedule/sensor testing 2/n][RFC] fxn to explicitly validate run config


[schedule/sensor testing 2/n][RFC] fxn to explicitly validate run config

This diff adds a function to validate run config against a pipeline.

I think the point of discussion here will be around what this fxn returns. @sandyryza noted, and I agree, that it would be cool to return something that represents the config after validation (there have been user issues opened regarding this). Should this post-validation config blob just mirror the config blob that we expect passed in? Bc after validation we throw it into EnvironmentConfig, and I don't think we want to make that user-facing.

Test Plan:
Will add more unit tests as we tamp down this and surrounding APIs. Will also cross over existing schedule tests in internal to see how it feels in practice.

API reference:

Screen Shot 2021-05-18 at 3.25.40 PM.png (787×1 px, 89 KB)

Reviewers: sandyryza, alangenfeld

Reviewed By: alangenfeld

Subscribers: sandyryza

Differential Revision: https://dagster.phacility.com/D7944