This task encompasses the work to start transitioning Gruntfile.js tasks to package.json in both MinervaNeue and Popups repos. This task covers all simple transitions such as ESLint and creating tasks for what remains. Delete any relevant dependencies as you go and [[ https://gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/extensions/MobileFrontend/+/master/package.json#3 | see MobileFrontend for reference ]] (T206069).
Before working on this, it is recommended to read through T206069, particularly around motivations and the patches that got merged. Apply the change logic to the Popups and Minerva repositories.
= Checklist of things to fix for each repo
 eslint is not using grunt
 stylelint is not using grunt
 jsonlint is not using grunt
 banana-checker is not using grunt
 grunt, grunt-contrib-watch and grunt-notify is removed from codebase