Add test code.
chore(project/dependencies): automatically include via maven

Instead of including dependencies in git repository, they are now
automatically included via maven-dependency-plugin.

BREAKING CHANGE:

You must execute `mvn clean install` on the project to copy the latest
modeler dependencies to the lib directories.
test(callactivity/namespace): Add test case for callActivity

- testcase to check namespace of call activity attributes

related to #CAM-1510
docs(contributing): Add hint on dependency unpack