Move to `thiserror` for error handling

[icorbrey]

Description

I want us to use thiserror for error handling instead of anyhow.

Use Case

It should allow us to be a lot more explicit about our errors and enable better logging.

Last Steps

• I agree to abide by this project's code of conduct.
• I would like to work on this and submit a PR with my changes.
  (Optional, but contributions are greatly appreciated!)