Use TypeScript

[jcbhmr]

This PR would... (checkboxes track draft progress)

• [x] add a npm pack prepack hook to run tsc
• [x] use TypeScript files instead of JavaScript files
• [x] remove the typings folder and use inline ts
• [x] continue using commonjs as the target (deal with that later)
• [x] add a tsconfig.json to the project
• [x] NOT add any additional files (yet)
• [x] NOT add a ci github workflow file (yet)
• [x] preserve the index.js entrypoint (deal with that later)
• [x] NOT change any of the logic code
• [x] PRESERVE the .version export
• [x] add dist folder to .gitignore
• [x] add package-lock.json to the project