Add Distributed Workload Generator

Closes #18 (closed), #16 (closed), #10 (closed), #28 (closed) .

uc1-workload-generator/src/main/java/theodolite/uc1/workloadgenerator/LoadGenerator.java

 package theodolite.uc1.workloadgenerator;
 
 import java.io.IOException;
+import java.time.Duration;
+import java.time.temporal.ChronoUnit;
 import java.util.Objects;
 import java.util.Properties;
-import java.util.concurrent.TimeUnit;
 import org.apache.kafka.clients.producer.ProducerConfig;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import theodolite.commons.workloadgeneration.communication.kafka.KafkaRecordSender;
-import theodolite.commons.workloadgeneration.dimensions.Duration;
 import theodolite.commons.workloadgeneration.dimensions.KeySpace;
-import theodolite.commons.workloadgeneration.dimensions.Period;
 import theodolite.commons.workloadgeneration.generators.KafkaWorkloadGenerator;
 import theodolite.commons.workloadgeneration.generators.KafkaWorkloadGeneratorBuilder;
 import theodolite.commons.workloadgeneration.misc.ZooKeeper;
@@ -23,7 +22,7 @@ public final class LoadGenerator {
 
   private static final Logger LOGGER = LoggerFactory.getLogger(LoadGenerator.class);
 
-  private static final int MAX_DURATION_IN_DAYS = 30;
+  private static final long MAX_DURATION_IN_DAYS = 30L;
 
   private LoadGenerator() {}
 
@@ -68,8 +67,8 @@ public final class LoadGenerator {
         KafkaWorkloadGeneratorBuilder.<ActivePowerRecord>builder()
             .setKeySpace(new KeySpace("s_", numSensors))
             .setThreads(threads)
-            .setPeriod(new Period(periodMs, TimeUnit.MILLISECONDS))
-            .setDuration(new Duration(MAX_DURATION_IN_DAYS, TimeUnit.DAYS))
+            .setPeriod(Duration.of(periodMs, ChronoUnit.MILLIS))
+            .setDuration(Duration.of(MAX_DURATION_IN_DAYS, ChronoUnit.DAYS))
             .setGeneratorFunction(
                 sensor -> new ActivePowerRecord(sensor, System.currentTimeMillis(), value))
             .setZooKeeper(new ZooKeeper(zooKeeperHost, zooKeeperPort))