Add nginx proxy hosts for Garage Web access

The respective bucket needs to be configured with a domain alias. When a
new alias is added to the `s3_web_domains` config, a new nginx site can
then be deployed to the `nginx_proxy` hosts.

environments/production.json

@@ -4,7 +4,10 @@
     "garage": {
       "replication_mode": "2",
       "s3_api_root_domain": ".s3.garage.kosmos.org",
-      "s3_web_root_domain": ".web.garage.kosmos.org"
+      "s3_web_root_domain": ".web.garage.kosmos.org",
+      "s3_web_domains": [
+        "s3.kosmos.social"
+      ]
     },
     "gitea": {
       "postgresql_host": "pg.kosmos.local:5432",
@@ -23,4 +26,4 @@
       ]
     }
   }
-}
+}