#78 - Clean up NER types

[reckart]

What's in the PR

• Drop 27 marker subtypes from NamedEntity type system (Person, Organization, Location, Date, Time, Money, Percent, Quantity, Ordinal, Cardinal, WorkOfArt, Animal, Plant, Substance, Disease, Event, Law, Language, ContactInfo, Game, Fac, FacDesc, Gpe, GpeDesc, Norp, OrgDesc, PerDesc, Product, ProductDesc, Nationality) — keep only NamedEntity with its value + identifier features
• Delete 11 per-model CoreNLP NER tag-to-type .map files; MappingProvider falls through to BASE_TYPE=NamedEntity and records the source tag in value
• Keep the generic NER mapping mechanism (MappingProviderFactory.createNerMappingProvider, mappingLocation parameter, ner-default-variants.map) so users can still supply custom .map files
• Rewrite DKPro2Gate to route GATE annotation types (Person/Location/Organization/NamedEntity) off NamedEntity.value instead of instanceof on subtypes; drop the now-redundant dkproType GATE feature
• Collapse the two GATE writer NER tests into one (oneWayNamedEntity); delete obsolete ner2002_conll.map + ner2002_ref_specific.xml; rename ner2002_ref_generic.xml → ner2002_ref.xml and update to expected GATE types
• Update brat reader/writer tests and .ann reference fixtures to use NamedEntity instead of Person/Location/Organization subtypes
• Update brat reader Javadoc example to reference NamedEntity instead of Location
• Update CoreNLP NER test assertions from Person(...)/Location(...)/Organization(...) to NamedEntity(...)
• Strip 30 deleted subtype entries from typesystemmapping.yaml; update brat documentation example to map (LOC|PER|ORG) → NamedEntity

How to test manually

• No specific test procedure

Automatic testing

• PR includes unit tests

Documentation

• PR updates documentation