Changes

[Doc] Fix documentation of EntityManager.getReference

Add info on when EntityNotFoundException is thrown.
 (commit: 0d99102)

[Ref] Replace remaining references to 'primaryKey' with 'identifier'.

Primary key is used in relational databases, JOPA does not work with them.
 (commit: 3d9cae1)

[Bug #257] Add test reproducing the issue.
 (commit: d174f73)

[Bug #257] Refactor element processing in modelgen to handle annotations in element type declaration.

In JDK 17 and before, annotations were added before type ("@Annotation java.util.Set"), now, they are inserted into the type ("java.util@Annotation Set"), so we cannot rely on TypeMirror.toString when determining type.
 (commit: 91c5414)

[Bug #257] Minor code cleanup in modelgen.
 (commit: 799b255)

[Enhancement #256] Add integration tests for the feature.
 (commit: 7d844e6)

[Enhancement #256] Add support for using URI/URL as data property values when mapped to simple literal.
 (commit: da4b4b1)

[Enhancement #245] Enable integration test testing the feature.

Disable the test for RDF4J, as it is not relevant there.
 (commit: bb84e2c)

[Enhancement #245] Flush reasoner before executing query to purge possibly stale reasoner cache.
 (commit: e6ceb1e)

[Update] Update to RDF4J 5.0.1.

Update Maven plugins and JUnit as well.
 (commit: 72a6675)

[Update] Update to Jena 5.1.0.
 (commit: 493cbc2)

[2.0.3] Bump version, update changelog.
 (commit: 5170f45)