Prepare Maven release support according to SonarTypes requirements

- Update POM definitions as required
- Generate & Provide -javadoc.jar files
Rework mvn call
Switch to Maven ant task instead manually calling mvn.
Use Maven install-Task for installing instead mvn-Task because javadoc/sources didn't work.
Ant targets & configuration for Central Maven Snapshot & Staging repository.
Merge branch 'feature/maven-deployment' into 3.0.x
Merge branch '3.0.x' of https://github.com/echo3/echo3 into exxcellent