Add shell-proxy plugin (#8692)

plugins/shell-proxy/ssh-proxy.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env python3
+import os
+import subprocess
+import sys
+import urllib.parse
+
+proxy = next(os.environ[_] for _ in ("HTTP_PROXY", "HTTPS_PROXY") if _ in os.environ)
+argv = [
+    "nc",
+    "-X",
+    "connect",
+    "-x",
+    urllib.parse.urlparse(proxy).netloc,  # proxy-host:proxy-port
+    sys.argv[1],  # host
+    sys.argv[2],  # port
+]
+
+subprocess.call(argv)