added matomo subdomain

deploy/external.json

@@ -59,6 +59,9 @@
         "blog.stratford.to": {
             "endpoint": "external-stratford-to"
         },
+        "seo.stratford.to": {
+            "endpoint": "external-stratford-to"
+        },
         "rancher.joos.to": {
             "endpoint": "external-joos-to"
         },