Add list of client connections per user (#26)

List the result of GET /_synapse/admin/v1/whois/<user_id>.

src/i18n/en.js

@@ -14,6 +14,7 @@ export default {
   },
   resources: {
     users: {
+      backtolist: "Back to list",
       name: "User |||| Users",
       email: "Email",
       msisdn: "Phone",
@@ -44,5 +45,13 @@ export default {
         joined_members: "Members",
       },
     },
+    connections: {
+      name: "Connections",
+      fields: {
+        last_seen: "Date",
+        ip: "IP address",
+        user_agent: "User agent",
+      },
+    },
   },
 };