Pipeline Graph Restructure: Graph Component Changes

What does this MR do?

This is the first MR in a series of MRs to restructure the main Pipeline Graph (see: #276949 (closed)). It covers renaming the existing graph components and specs to _legacy and adding new data structures for the new specs.

I'm sorry it looks like so many lines of code but 900 of them are renamed files.

All this work is behind the :graphql_pipeline_details flag, which is off.

Screenshots (strongly suggested)

With the flag off, the graph appears as normal.

Does this MR meet the acceptance criteria?

Conformity

• Code review guidelines
• Merge request performance guidelines
• Style guides

Availability and Testing

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

Related to #276949 (closed)