Add shell-proxy plugin (#8692)

plugins/shell-proxy/ssh-agent.py

@@ -0,0 +1,16 @@
+#!/usr/bin/env python3
+import os
+import subprocess
+import sys
+
+ssh_proxy = os.path.join(os.path.dirname(__file__), "ssh-proxy.py")
+
+argv = [
+    os.environ.get("NAME", "ssh"),
+    "-o",
+    "ProxyCommand={} %h %p".format(ssh_proxy),
+    "-o",
+    "Compression=yes",
+]
+
+subprocess.call(argv + sys.argv[1:], env=os.environ)