[UIMA-3869] Better maven-plugin-plugin configuration
- Configure extractors in parent-pom
- Configure helpmojo in parent-pom
- Now all maven-plugin-plugin configuration can be removed in the modules

git-svn-id: https://svn.apache.org/repos/asf/uima/build/trunk@1601614 13f79535-47bb-0310-9956-ffa450edef68