Implemented login through command line arguments

* Moved Config and ConfigItem to data package
* Added mandatory property to ConfigItem
* Added user and password ConfigItems to Config

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

@@ -9,8 +9,8 @@ import java.util.logging.Logger;
 
 import javax.naming.TimeLimitExceededException;
 
-import envoy.client.Config;
 import envoy.client.data.Cache;
+import envoy.client.data.Config;
 import envoy.client.data.LocalDb;
 import envoy.client.util.EnvoyLog;
 import envoy.data.*;