add system property to override download path

Signed-off-by: Stephane Bouchet <[email protected]>

src/main/java/com/redhat/devtools/intellij/common/utils/DownloadHelper.java

@@ -39,7 +39,6 @@
 import java.io.OutputStream;
 import java.io.StringReader;
 import java.net.URL;
-import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;