Use a copy of the new PerMessageDeflateExtension

A new PerMessageDeflateExtension was contributed to the Java-WebSocket
project, but no new release of that library has been made since.

Add a copy of the new implementation with an adapted package path and
use that instead of the old version from Java-WebSocket 1.6.0.

This is intended to be a temporary measure until a newer release of the
Java-WebSocket library is made. When that is updated, this change can be
reverted.

Author: robert-s-ubi

ocpp-v2/src/main/java/eu/chargetime/ocpp/MultiProtocolJSONClient.java

@@ -44,7 +44,6 @@
 import org.java_websocket.drafts.Draft;
 import org.java_websocket.drafts.Draft_6455;
 import org.java_websocket.extensions.IExtension;
-import org.java_websocket.extensions.permessage_deflate.PerMessageDeflateExtension;
 import org.java_websocket.protocols.IProtocol;
 import org.java_websocket.protocols.Protocol;
 import org.slf4j.Logger;

ocpp-v2/src/main/java/eu/chargetime/ocpp/MultiProtocolJSONServer.java

@@ -43,7 +43,6 @@ of this software and associated documentation files (the "Software"), to deal
 import org.java_websocket.drafts.Draft;
 import org.java_websocket.drafts.Draft_6455;
 import org.java_websocket.extensions.IExtension;
-import org.java_websocket.extensions.permessage_deflate.PerMessageDeflateExtension;
 import org.java_websocket.protocols.IProtocol;
 import org.java_websocket.protocols.Protocol;
 import org.slf4j.Logger;