Add top-level package for Java implementation

Package structure will then be something like spesb.uc4.app-kafka-streams

changed milestone to %0.1.0

assigned to @stu202077

added modul/benchmarks label

added In Progress label

mentioned in merge request !3 (merged)

removed In Progress label

added In Progress label

closed via merge request !3 (merged)

mentioned in commit e8e74457