Provide examples for python podman API

Signed-off-by: Jhon Honce <jhonce@redhat.com>

Closes: #870
Approved by: rhatdan

contrib/python/examples/eg_image_list.py

@@ -0,0 +1,10 @@
+#!/usr/bin/env python3
+"""Example: Show all images on system."""
+
+import podman
+
+print('{}\n'.format(__doc__))
+
+with podman.Client() as client:
+    for img in client.images.list():
+        print(img)