Simple grouping for Monitor ping + query pings

**Describe your feature request**:
Given a possibility to create a group identified by just it's name and a section where you can manage the belonging domains to such group/collection. Given this the Monitor ping interface would become more like a list of groups and domains as its children. Like:
```
-> Group 1 ---------------------------------------------------- [quick statistics] [open/close arrow]
- example.com
- example.org
- etc.
```
that can be opened or closed.

As a second inclusive feature it would be nice to be also able to add pings against full query paths and give a more descriptive "Name" to each ping, something similar to what I can do in this [android app](https://play.google.com/store/apps/details?id=com.maoux.ismyserveronline):

I'm open to sponsoring this feature request, just let me know to what it would amount.

Monitor の ping インターフェースから始め、監視対象ドメインと ping 名が現在どのように表現されているかを追跡します。実装前に、グループ階層、ドメイン管理、query-path の完全なサポート、説明的な名前を明確にします。完了とは、グループを開閉でき、ドメイン ping と query-path ping の両方をカスタム名で管理できることです。

索引モデルが issue の本文から書いたものです。