Write an intro + prereqs section for the tutorial.

In the first part of the NPM walkthrough tutorial, provide step by step instructions on how to install Magnolia and create a working light module only using CLI commands.

See https://documentation.magnolia-cms.com/display/DOCU/NPM+CLI+walkthrough+meeting+notes for the bare bones structure and order of steps.

See https://documentation.magnolia-cms.com/display/DOCS/Creating+a+light+module+using+Magnolia+CLI for a draft of the page