Replace Kubernetes YAML sed-replacements by Kustomize

Closes #17 (closed)

Change infrastructure of Kubernetes files for the uc applications and workload generators. The new structure is:
--uc-application
---- base
---- overlay
-------uc1-application
-------uc2-application

Also use Kustomize for building the files for deployment

execution/uc-application/base/aggregation-deployment.yaml

@@ -23,7 +23,7 @@ spec:
         - name: KAFKA_BOOTSTRAP_SERVERS
           value: "my-confluent-cp-kafka:9092"
         - name: COMMIT_INTERVAL_MS
-          value: 100
+          value: "100"
         - name: JAVA_OPTS
           value: "-Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.port=5555"
         resources: