Solid -> Node
Another in the rename stream, just changes the type name. Variables etc to be updated in future.
I think it'll be useful to have something like Node[Solid] & Node[Graph] or SolidNode and SolidGraph to distinguish, but for now just reflect the existing code operating in terms of a single type with getters to distinguish.
depends on D8714
Test Plan: bk
Reviewers: owen, yuhan, cdecarolis, prha
Reviewed By: owen
Differential Revision: https://dagster.phacility.com/D8715