Merge branch 'feature/useAvro' into feature/app-wg-with-avro

...va/theodolite/commons/kafkastreams/ConfigurationKeys.java

.../theodolite/commons/kafkastreams/KafkaStreamsBuilder.java

build.gradle

execution/uc1-application/aggregation-deployment.yaml

execution/uc1-workload-generator/deployment.yaml

execution/uc2-application/aggregation-deployment.yaml

execution/uc2-workload-generator/deployment.yaml

execution/uc3-application/aggregation-deployment.yaml

execution/uc3-workload-generator/deployment.yaml

execution/uc4-application/aggregation-deployment.yaml

execution/uc4-workload-generator/deployment.yaml

...in/java/theodolite/uc1/application/ConfigurationKeys.java

.../main/java/theodolite/uc1/application/HistoryService.java

...java/theodolite/uc1/streamprocessing/TopologyBuilder.java

...eodolite/uc1/streamprocessing/Uc1KafkaStreamsBuilder.java

...cation/src/main/resources/META-INF/application.properties

...n/java/theodolite/uc2/application/AggregationService.java

...theodolite/uc2/streamprocessing/JointFlatTransformer.java

...ite/uc2/streamprocessing/JointFlatTransformerFactory.java

...a/theodolite/uc2/streamprocessing/JointRecordParents.java