prettier: install prettier and eslint

[julesvirallinen]

commits readable in order

• adds prettier as near as possible to current styling
  • two spaces, semicolons etc.
• adds eslint with a few recommended rules
  • and e.g. function spacing for legibility
• kills any's and a couple other type funks

(also bumps node to 18, if we're not ready for that, then eslint needs debumping)
(PS i'd very strongly recommend committing package.lock as is standard, removes a lot of friction when working with node)

If we get this in I can add commit hook to lint / github action check / whatever.

[saml-dev]

sounds great, thanks. feel free to add whatever package-lock.json you have on your next PR, I live on the wild side and fresh npm install when I cut a release 😅

[julesvirallinen]

wild! let's lock in the node version and package-lock, should save a lot of trouble in the future :D stuff like this can cause major pain when stuff needs to be upgraded and people have different envs :D