add getting started video 02: installing node and updating npm

Here's the second Getting Started video. If you'd like to review and comment, please feel free to!

https://www.youtube.com/watch?v=wREima9e6vk

Before merge, these must be done:
- [x] @rod11 reviews
- [x] @iarna reviews
- [x] Lin smooths out vocals
- [x] Lin adds text