Update Day 9 Interactive Session

[ryoliver]

This is a lighter day, which seems fine, but the interactive session could be clearer.

Instead, I suggest that this session focus on:

1. creating a reproducible example using reprex
2. storing/sourcing custom ggplot themes as functions
3. making pretty tables with kableExtra

Suggest the following edits:

1. Remove section 3 (very short and a bit disjointed from other content)
2. Move section 5 (creating custom ggplot theme as function) to section 3
3. Replace section 4 with content from Day 10 Interactive Session

Could additionally expand the kableExtra section to provide a more comprehensive overview of the basics