Add benchmark implementations for Apache Flink

added modul/benchmarks label

mentioned in issue #96 (closed)

This is already implemented in @stu209212's Bachelor's thesis and only has to be migrated to the recent version of Theodolite. Current implementation can be found in the apache-flink branch.

mentioned in merge request !90 (merged)

mentioned in issue #165

added modul/benchmarks/flink label

removed modul/benchmarks label

mentioned in commit e979a39e

closed with merge request !90 (merged)