Publish global CLI app to npm

[Glavin001]

This should also make it easier to install ( #23 ).

TODO:

• running CLI will check the current working directory for files
  • gitlab-pages-config.js config file
    • Add YAML support for gitlab-pages-config.yml
    • If does not exist, walk user through creating one. Answer the following questions:
      • Server URL
      • Deploy branch
      • Temporary pages directory
      • Public Pages directory
      • Page to SSH public and private keys
        • How to create SSH key pair
• publish to npm as gitlab-pages

[Glavin001]

Use https://www.npmjs.com/package/inquirer for asking questions when generating config file.