Add default metadata for public network

Add deafult value for all models
Metadata will be replace in deployment by steps
from shared-salt:
https://github.com/Mirantis/tcp-qa/blob/master/tcp_tests/templates/shared-salt.yaml#L431

Change-Id: I99f4daaa0aee28ca6eca3b9cae3cc380c749d58d
diff --git a/tcp_tests/templates/cookied-cicd-k8s-calico-sl/environment-context-k8s-sl.yaml b/tcp_tests/templates/cookied-cicd-k8s-calico-sl/environment-context-k8s-sl.yaml
index 4abe271..eee2067 100644
--- a/tcp_tests/templates/cookied-cicd-k8s-calico-sl/environment-context-k8s-sl.yaml
+++ b/tcp_tests/templates/cookied-cicd-k8s-calico-sl/environment-context-k8s-sl.yaml
@@ -256,3 +256,10 @@
           role: single_dhcp
         ens4:
           role: single_ctl
+
+environment_metadata:
+    public_gateway: 172.17.16.1
+    public_cidr: 172.17.16.0/24
+    public_allocation_start: 172.17.16.201
+    public_allocation_end: 172.17.16.245
+    tempest_test_target: gtw01*