Generate Static Name Property

[daogrady]

Generated classes (both for singular and plural) will now contain a static .name property which contains the fully qualified name of the entity it was generated from.

namespace 'sap.bookshop';

entity Books {}

⬇️ (more or less)

// sap/bookshop/.index.ts
class Book {
  static name = 'sap.bookshop.Books'
}

class Books extends Array<Book> {
  static name = 'sap.bookshop.Books'
}

This allows the class and its transpiled form to be used as parameter for CDS functions that expect CSN definitions. Those will look for a .name property and use that as lookup key in the compiled CSN.

This PR is therefore a step towards using the transpiled index.js files in a TypeScript context.

Note that .name is actually a reserved name, so we have to forcefully inject it into the generated classes. This does not seem to be an issue, but should be kept an eye on.