prospecto collection syntax improvement

collections.md

This is the current syntax...

mapOfObjects(Role.class, Contributor.class)
    .reference("person", PERSON_SUMMARY_TEMPLATE)
    .arrayOfObjects("credits")
          .reference("responsibleOrganization", ORG_SUMMARY_TEMPLATE)
          .value("percentCredit")
          .end()

What if we separate the method that specifies a collection (e.g. array or map) from the thing it contains? For example, we could have a syntax like this...

map(Role.class)
    .object(Contributor.class)
        .reference("person", PERSON_SUMMARY_TEMPLATE)
        .array("credits")
            .object(Credit.class)
                .reference("responsibleOrganization", ORG_SUMMARY_TEMPLATE)
                .value("percentCredit")
                .end()

The map and array methods create a builder that has a just a few methods on it.

interface CollectionBuilder {
  
  CollectionBuilder map(...);

  CollectionBuilder array(...);

  ViewTemplateBuilder object(...);

  ViewTemplateBuilder value(...);

}

The cool new thing this approach allows is collection composition.

map(Role.class)
    .array()
        .object(Contributor.class)
            .reference("person", PERSON_SUMMARY_TEMPLATE)
            .array("credits")
                .object(Credit.class)
                    .reference("responsibleOrganization", ORG_SUMMARY_TEMPLATE)
                    .value("percentCredit")
                    .end()

So I can have a map whose entries are arrays, or an array of arrays, or an array of maps, etc.