USDM 4.0.0 regression test updates

[jonmassoncap]

Added the 4.0.0 regression test data, taken from the CDISC_Pilot example from the RA repository.

Copied the V4 unit tests and then adapted them to work with the v4.0.0 regression test data.

In a few cases, there was a discrepancy between the UML model and the shape of the regression test data, this was usually because the data json contained just an ID reference to something, while the model had the actual object as a property rather than an ID reference. For a concrete example of this, the regression data json had AnalysisPopulationId property on the estimands, but in the model, estimands have an actual AnalysisPopulation as the property, not just the ID. I generally assumed that the model design was correct, and adjusted the data json to fit this. This is because looking at older versions of the JSON, this is how it has been done in the past, and it's also much easier than updating the model design.

While reviewing this, it may be easier to look at the commit history to see what changes were made to the json after copying in the raw data from the RA repository.

All regression tests are now running and passing.