Changed compiler compliance to 11, modularized all packages (#114)

* added module- and package-info.java, changed JRE from 8 to 11

* updated maven from Java 1.8 to 11

Co-authored-by: CyB3RC0nN0R <kske@outlook.de>

src/main/java/envoy/client/net/Client.java

@@ -85,7 +85,7 @@ public class Client implements Closeable {
 		rejected = false;
 
 		// Start receiver
-		new Thread(receiver).start();
+		receiver.start();
 
 		// Write login credentials
 		SerializationUtils.writeBytesWithLength(credentials, socket.getOutputStream());