QI-384 NamedAssociations

NamedAssociation support based on 1.4 API.

The whole SDK is impacted where appropriate.

In some places the support is incomplete:
- everywhere ManyAssociations where already unsupported
- RDF Indexing
- SQL Indexing
Merge branch 'feature/named-associations-2' into develop

Whitespace conflict:
	extensions/indexing-elasticsearch/src/main/java/org/qi4j/index/elasticsearch/ElasticSearchFinder.java