Update Day 8 Interactive Session

[ryoliver]

The interactive session currently includes a LOT of ggplot bells and whistles, but doesn't really force them to think critically about creating a few good data visualizations. It would be nice to focus on the basic tools and instead reinforce stylistic concepts. Again, could be fun to work with real data and ask them to do data cleaning/wrangling to get it in the right format for plotting in ggplot.

Suggest updating the interactive session to more clearly focus on the following key basics:

1. essential items (defining data, aes(), and geometry type)
2. mapping with aesthetics (constants and variables)
3. updating aesthetics with scales:: (both axes and colors)
4. updating color palettes by using custom palette packages and scale_ functions
5. updating theme elements using built-in themes and tweaking them elements
6. creating compound figures with patchwork

These pieces are all in the current interactive session, but I think restructuring the order and more clearly articulating that these are the key tools would be helpful. Suggest adding in more examples for each step and building to one really pretty compound figure. Everything else could be moved to bonus! Didn't make any of this extra stuff!