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/uc1-workload-generator/deployment.yaml

-apiVersion: apps/v1
-kind: Deployment
-metadata:
-  name: titan-ccp-load-generator
-spec:
-  selector:
-    matchLabels:
-      app: titan-ccp-load-generator
-  replicas: {{INSTANCES}}
-  template:
-    metadata:
-      labels:
-        app: titan-ccp-load-generator
-    spec:
-      terminationGracePeriodSeconds: 0
-      containers:
-      - name: workload-generator
-        image: theodolite/theodolite-uc1-workload-generator:latest
-        env:
-        - name: ZK_HOST
-          value: "my-confluent-cp-zookeeper"
-        - name: ZK_PORT
-          value: "2181"
-        - name: KAFKA_BOOTSTRAP_SERVERS
-          value: "my-confluent-cp-kafka:9092"
-        - name: SCHEMA_REGISTRY_URL
-          value: "http://my-confluent-cp-schema-registry:8081"
-        - name: NUM_SENSORS
-          value: "{{NUM_SENSORS}}"
-        - name: POD_NAME
-          valueFrom:
-            fieldRef:
-              fieldPath: metadata.name
-        - name: INSTANCES
-          value: "{{INSTANCES}}"