Pipeline Graph Structural Update: Pre Refactor I

What does this MR do?

This MR does some basic cleanup to prepare for more meaty changes to the big pipeline graph. It is not behind a feature flag.It has no effect on behavior, but renames methods to match the new names that will come from GraphQL.

Screenshots (strongly suggested)

up and down	down and down more

Does this MR meet the acceptance criteria?

Conformity

• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.