Extract the kafka streams and flink use case and load generator
and commons dependencies to a convention plugin to reduce the
complexety of the main build gradle file.

Create convention plugins to reduce complexity of the root build.gradle file

The Project is renamed to theodolite and therefore all packages
should be renamed likewise.

Add the spesb prefix to all self implemented java packages of the
project. Because this changes the fully qualified class name of
the main classes the build.gradle files need to adopt to this.