#2320 add root_run_id to group related runs
root_run_id will be created when users hit re-execution on either Run Table or Run.
If it's a new run without children, it won't have this tag, because the current logic is to create the tag in re-execution func.
- refactored getExecutionVariables in Run and RunTable
- consolidated names of the buttons that are using RunActionButtons
Reviewers: max, alangenfeld, prha
Reviewed By: max, alangenfeld
Differential Revision: https://dagster.phacility.com/D2336