Review and update Getting Started page

[ChrisWiegman]

This ticket is the first in what will be a series of tickets to review and improve our documentation on faustjs.org.

Let's start with https://faustjs.org/tutorial/get-started-with-faust. Review the page, run the instructions as a user and improve it where we can.

Note: take a moment to go through the Discord/support channels to ensure any relevant feedback for this page is added.