Connected clients admin API (#217)

* Add support for ending the inbound stream. Closes #191

* Add a simple success response to API requests

* Connected clients API with geo details

* Post-rebase cleanup

* Make setting and reading geo details separate operations to unblock and speed up

* Rename file

* Fire geoip api call behind goroutine

* Add comment

* Post-rebase fixes

* Add support for the MaxMind GeoLite2 GeoIP database

core/chat/chat.go

@@ -70,3 +70,12 @@ func GetMessages() []models.ChatMessage {
 
 	return getChatHistory()
 }
+
+func GetClient(clientID string) *Client {
+	for _, client := range _server.Clients {
+		if client.ClientID == clientID {
+			return client
+		}
+	}
+	return nil
+}