add getting started video 09: uninstalling global packages

Here's the 9th Getting Started video. If you'd like to review and comment, please feel free to!

https://www.youtube.com/watch?v=B-yV1gypZKQ

Before merge, these must be done:
- [ ] @rod11 reviews
- [ ] @iarna reviews
- [ ] Lin smooths out vocals
- [ ] Lin adds text