Change default folder for wsconsume generated sources

The Maven convention for generated sources is for those to be created under target/generated-sources/blabla. The AbstractWsConsumeMojo class specifies that sources be created under target/wsconsume/java (through the default-value of the sourceDirectory param).

I suggest this is changed to "${project.build.directory}/generated-sources/wsconsume". (I don't see a need for adding a trailing "java".)