METAGEN-83 Updating versions of dependencies and Maven plugins

Here is an update of the dependencies and the Maven plugins.

I tested a mvn package javadoc:javadoc org.jboss.maven.plugins:maven-jdocbook-plugin:2.3.8:resources org.jboss.maven.plugins:maven-jdocbook-plugin:2.3.8:generate assembly:assembly without any problem (except for the failing tests being worked on in METAGEN-85).

I had to change a class due to a change in Jaxb but it's very minor.

Note: except for the JBoss specific plugins, we are using these versions for a while in our apps without any problem.