Create api+scenario tests for l7rules

This patch implements l7rule tests for the Octavia
Tempest Plugin.

Change-Id: Iba7fa5979eab05bf368fd8554e92563b22c7ca79
Story: 2001387
Task: 5972
diff --git a/octavia_tempest_plugin/clients.py b/octavia_tempest_plugin/clients.py
index bb08c3b..14381f2 100644
--- a/octavia_tempest_plugin/clients.py
+++ b/octavia_tempest_plugin/clients.py
@@ -20,6 +20,8 @@
 from octavia_tempest_plugin.services.load_balancer.v2 import (
     l7policy_client)
 from octavia_tempest_plugin.services.load_balancer.v2 import (
+    l7rule_client)
+from octavia_tempest_plugin.services.load_balancer.v2 import (
     listener_client)
 from octavia_tempest_plugin.services.load_balancer.v2 import (
     loadbalancer_client)
@@ -49,3 +51,5 @@
             self.auth_provider, SERVICE_TYPE, CONF.identity.region)
         self.l7policy_client = l7policy_client.L7PolicyClient(
             self.auth_provider, SERVICE_TYPE, CONF.identity.region)
+        self.l7rule_client = l7rule_client.L7RuleClient(
+            self.auth_provider, SERVICE_TYPE, CONF.identity.region)