Generate TypeScript classes for DDI 4.0

[borsna]

Similar to the existing csharp classes that is generated when DDI 4 (https://github.com/ddialliance/ddimodel)

The build process with https://github.com/colectica/cogs does the code generation.
It could also be done by using jsonSchema.json (after #17 is resolved) or dctap.csv (Dublin Core Tabular Application Profile)

[DanSmith]

If using the json schema as a source, ddialliance/ddimodel#61 may need to be resolved first.

[DanSmith]

The updated json schema with ddialliance/ddimodel#61 addressed is at:
https://docs.ddialliance.org/DDI-Lifecycle/dev/output/jsonSchema.json