Draft: Add Spark Structured Streaming based Benchmarks

This merge request includes Spark Structured Streaming benchmarks for use-cases 1 to 3. Furthermore, all necessary resources for execution with Theodolite on a Kubernetes cluster are included.

theodolite-benchmarks/uc1-spark/src/main/resources/META-INF/application.properties

+application.name=theodolite-uc1-application
+application.version=0.0.1
+
+kafka.bootstrap.servers=localhost:9092
+kafka.input.topic=input
+schema.registry.url=http://localhost:8081
+time.zone=Europe/Paris