Pris 112 update maven asciidoctor plugin

JIRA: http://issues.opennms.org/browse/PRIS-112

- Update asciidoctor version 0.1.4 to 1.5.0
- Introduce asciidoctor version property
- Cleanup unused version properties
- Introduced missing version proberties
- Changed toc from right to left, for similar layout than opennms doc