Add a module for managing packages for the Atom editor

You can try this module with my [atom-packages](https://galaxy.ansible.com/list#/roles/1005) role for Ansible.

To install the Atom editor, please run the following commands:

```shell-session
brew tap caskroom/cask
brew install brew-cask
brew cask install atom
```

Or you can use my [homebrew-cask-packages](https://galaxy.ansible.com/list#/roles/1004) role for Ansible.