Migrate to styled-system v5

**Is your feature request related to a problem? Please describe.**
Migrate to styled-system v5.

**Describe the solution you'd like**
We should migrate our components to use styled-system v5 to take advantage of new features like prop-types, style categories, and new Custom Styles api.

**Describe alternatives you've considered**
Staying in v4.

**Additional context**
https://styled-system.com/guides/migrating

Acceptance criteria:
- should have styled-system v5 branch
- should upgrade any api changes to components
- should write down any documentation changes that are needed
- verify no components broke
- verify all component styles still work
- should accept all styled-system v5 props
E: 1D