Add iptables-based active/standby scenario test

This patch adds a tempest scenario test for active/standby topology.

This scenario takes a similar approach to scenario proposed in Change-Id
Ibcd5552a67cea650edc72bfaa986357267ca2407 with the difference that it
does not rely on amphora stats API. Instead, it uses iptables to log VIP
traffic and make assertions based on logging.

Co-Authored-By: Michael Johnson <johnsomor@gmail.com>

Change-Id: I24a6fc3387166ec6cdbd57a5ca9f63743748ec68
diff --git a/octavia_tempest_plugin/config.py b/octavia_tempest_plugin/config.py
index 701eb8e..cd8012e 100644
--- a/octavia_tempest_plugin/config.py
+++ b/octavia_tempest_plugin/config.py
@@ -151,8 +151,15 @@
     cfg.StrOpt('member_2_ipv6_subnet_cidr',
                default='fd77:1457:4cf0:26a8::/64',
                help='CIDR format subnet to use for the member 1 ipv6 subnet.'),
+    # Amphora specific options
+    cfg.StrOpt('amphora_ssh_user',
+               default='ubuntu',
+               help='The amphora SSH user.'),
+    cfg.StrOpt('amphora_ssh_key',
+               default='/tmp/octavia_ssh_key',
+               help='The amphora SSH key file.'),
     # Environment specific options
-    # These are used to accomidate clouds with specific limitations
+    # These are used to accomodate clouds with specific limitations
     cfg.IntOpt('random_server_name_length',
                default=0,
                help='If non-zero, generate a random name of the length '