Added synctrans URL parameters endpoint (GET convenience mode) and improved protocol negotiation

src/main/java/it/inaf/oats/vospace/exception/InvalidArgumentException.java

+package it.inaf.oats.vospace.exception;
+
+import net.ivoa.xml.uws.v1.ErrorSummaryFactory;
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+@ResponseStatus(value = HttpStatus.BAD_REQUEST)
+public class InvalidArgumentException extends VoSpaceErrorSummarizableException {
+
+    public InvalidArgumentException(String message) {
+        super(message, ErrorSummaryFactory.VOSpaceFault.NODE_NOT_FOUND);
+    }
+}