remove »Play with Moby« website

The project itself is archived and the CNAME for Github pages was deleted
[63f0a75] on 2020-01-31.

TravisCI [#2884]:

> Issues :-(
>
> > Links
> 1. [L104] 404 http://play-with-moby.com/
> 2. [L475] 404 https://github.com/puppetlabs/europa
> > Dupes
> None ✓

[63f0a75] 63f0a75737
[#2884] 644869685

README.md

@@ -101,7 +101,6 @@ _Source:_ [What is Docker](https://www.docker.com/why-docker)
 - [Katacoda](https://www.katacoda.com/courses/docker): Learn Docker using Interactive Browser-Based Labs
 - [Learn Docker](https://github.com/dwyl/learn-docker): step-by-step tutorial and more resources (video, articles, cheat sheets) by [@dwyl](https://github.com/dwyl)
 - [Play With Docker](https://training.play-with-docker.com/): PWD is a great way to get started with Docker from beginner to advanced users. Docker runs directly in your browser.
-- [Play With Moby](http://play-with-moby.com/): PWM is a web based Moby playground which allows you to try different components of the platform in seconds. It gives you the experience of having a free Alpine Linux Virtual Machine in the cloud where you can build and run Moby projects and even create clusters to experiment.
 - [Practical Introduction to Container Terminology](https://developers.redhat.com/blog/2018/02/22/container-terminology-practical-introduction/) The landscape for container technologies is larger than just docker. Without a good handle on the terminology, It can be difficult to grasp the key differences between docker and (pick your favorites, CRI-O, rkt, lxc/lxd) or understand what the Open Container Initiative is doing to standardize container technology.
 
 **Cheatsheets** by