Add download support to CLI and client

Implemented file and folder download functionality in the CLI and GofileClient, including new CLI arguments for downloading by URL or content ID and specifying output directory.

test_download.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env python3
+"""Test script for download functionality."""
+
+from gofilepy import GofileClient
+
+# Test downloading from the folder URL
+client = GofileClient()
+
+# Get folder contents
+contents = client.get_contents("GxHNKL")
+print("Folder contents:")
+print(contents)
+
+# You can also download programmatically like this:
+# client.download_file(
+#     download_url="https://store-eu-par-6.gofile.io/download/web/folder-id/file.py",
+#     output_path="./downloaded_test.py"
+# )