Refresh the homepage and improve export and draft guidance

tests/java/UploadSmoke.java

@@ -0,0 +1,9 @@
+import dev.minegeo.plugin.UploadClient;
+import com.google.gson.JsonParser;
+import java.nio.file.*;
+public class UploadSmoke {
+  public static void main(String[] args) throws Exception {
+    String token=JsonParser.parseString(Files.readString(Path.of(args[2]))).getAsJsonObject().get("token").getAsString();
+    new UploadClient(args[0],token).upload(Path.of(args[1]),message->System.out.println(message),()->false);
+  }
+}