Add examples for Cat-VRS data classes

[DanielPuthawala]

It was expressed at the last Cat-VRS call that having examples alongside the schemata and docs really helped people new to the project to orient themselves. It was requested that we add additional examples (2 or 3 per class?) that demosntrate different aspects of the schemas.

[brendanreardon]

A non-exhaustive list of example updates that we want to make:

• Create a DefiningLocation constraint example that starts and ends with ranges, per Bob Dolin's recommendation
• Add HGVS mappings for all relevant examples
• Add an example that uses DefiningLocationConstraint with anyOf

[brendanreardon]

I just noticed that this thread may be a duplicate of #25. Should we close this in favor of the earlier one from Kori?