Exokit inspector

[avaer]

Currently we use node console/repl for debugging, but we could do much better. We've considered:

• https://github.com/christian-bromann/devtools-backend
• https://github.com/krishnasrinivas/wetty
• https://github.com/GoogleChromeLabs/ndb

Each have their own advantages/disadvantages. I'm learning towards ndb since we already use puppeteer for doing legacy 2D...

[avaer]

Related: https://github.com/webmixedreality/exokit/issues/262