PileUp digitization new configuration
Migrate a chunk of PileUp digitization to new config.
Add PileUpConfigNew, MCTruthSimAlgsConfigNew and RunDependentConfigNew, using ComponentAccumulator configuration.
Add various flags under Digitization.PU.
Add DigitizationPUConfigNew_test.py
to test. This checks that parts of the new configuration code can run, but is not yet a runnable configuration.
Large test setup data are imported from a _setup.py file.