Add script to compile source TypeScript

[chaance]

npm run compile will compile everything in apps and courses into a compiled directory. TypeScript will be compiled to javascript, while everything else will be copied as-is.

Everything should be compiled as close to the source as possible. The only thing that kind of sucks is that the TS compiler cannot preserve whitespace, so even with prettier the output might not look exactly the same as you might intend.

This won't affect any of the existing curriculum code (other than the fact that I updated prettier, but feel free to revert if you'd like). To test this, you can rename apps/YesterTech/App.js to apps/YesterTech/App.tsx, run the script, and check the output file compiled/apps/YesterTech/App.js.

[bradwestfall]

@chaance works great 🎉