chore: standardize usage of config files

[achou11]

The unofficial convention for configuring different tooling has moved towards having a file named <name>.config.js for each tool that supports it. In most cases, tools support a variety of configuration approaches but in general, I prefer using a config file when possible because it allows for types-based checking + assistance when writing/updating the configuration, which is massively useful.

This PR does the following:

• ports the jest configuration from package.json to jest.config.js
• ports the lint-staged configuration from package.json to lint-staged.config.js
• ports the prettier configuration from .prettierrc.js to prettier.config.js

ESLint is notably omitted here because it requires upgrading to v9 in order to use this config file convention. That work is addressed via #897