feat: add prettier and eslint

[Trickfilm400]

Hi,

Based on #310 (comment) here is a follow-up PR with prettier and a simple eslint configuration for styling the project files

Can we do a 5.0.0 release after this, so the NPM package corresponds to the current readme? Could be confusing otherwise. (the pipeline seems broken, issue seems like a wrong NPM token, therefore the 401 error, FWIK)

Changes:

• add eslint, eslint-plugin-mocha, prettier
• run prettier on all files
• update a re-export of is-ip

First step for #318

/cc @43081j

[43081j]

could you possibly copy the prettier config from chai-as-promised:
https://github.com/chaijs/chai-as-promised/blob/master/.prettierrc.json

if we decide to change some preferences, at least the repos are in sync then

ill open a separate PR to sort the publishing

[43081j]

one last comment, could you also add the editorconfig from here:
https://github.com/chaijs/chai-as-promised/blob/master/.editorconfig

looks good to me then 👍 super nice work 🙏