Bump to HAL 2.2.3.Final

Summary of changes:

- Changed version of parent pom to `org.jboss.teiid:teiid-parent:pom:8.6.0.Final` (`org.jboss.teiid:teiid-parent:pom:8.4.1` could not be found?)
- Added JBoss Nexus (plugin) repositories (to fix missing dependencies)
- Bumped to HAL 2.2.3.Final
- Fixed import statements