MINOR/DOC: spoe-server: Add documentation

This is the documentation and examples.
diff --git a/contrib/spoa_server/ps_python.py b/contrib/spoa_server/ps_python.py
new file mode 100644
index 0000000..108eb48
--- /dev/null
+++ b/contrib/spoa_server/ps_python.py
@@ -0,0 +1,20 @@
+from pprint import pprint
+import spoa
+import ipaddress
+
+def check_client_ip(args):
+	pprint(args)
+	spoa.set_var_null("null", spoa.scope_txn)
+	spoa.set_var_boolean("boolean", spoa.scope_txn, True)
+	spoa.set_var_int32("int32", spoa.scope_txn, 1234)
+	spoa.set_var_uint32("uint32", spoa.scope_txn, 1234)
+	spoa.set_var_int64("int64", spoa.scope_txn, 1234)
+	spoa.set_var_uint64("uint64", spoa.scope_txn, 1234)
+	spoa.set_var_ipv4("ipv4", spoa.scope_txn, ipaddress.IPv4Address(u"127.0.0.1"))
+	spoa.set_var_ipv6("ipv6", spoa.scope_txn, ipaddress.IPv6Address(u"1::f"))
+	spoa.set_var_str("str", spoa.scope_txn, "1::f")
+	spoa.set_var_bin("bin", spoa.scope_txn, "1:\x01:\x02f\x00\x00")
+	return
+
+
+spoa.register_message("check-client-ip", check_client_ip)