Migrated from JSHint to ESLint

[Nishthajain7]

Fixes #1540

Changes: Updated the preprocessing lint step to use ESLint instead of JSHint.

I have verified that this pull request:

• has no linting errors (npm run lint)
• has no test errors (npm run test)
• has no typecheck errors (npm run typecheck)
• is from a uniquely-named feature branch and is up to date with the develop branch.
• is descriptively named and links to an issue number, i.e. Fixes #123
• meets the standards outlined in the accessibility guidelines

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[khanniie]

Hi! Thank you so much for the contribution! If this is regarding the codemirror 5 to 6 migration, the subissue we published was actually regarding the js linter used within the Editor/stateUtils.js file. I do think the approach is correct, it would be great if you could move the changes to that file!

[Nishthajain7]

Sorry for the delay. There were a lot of emails, and this one slipped through. I've moved the changes to stateUtils.js

[khanniie]

Hi Nishthajain7! I checked out the branch and it doesn't build properly -- it looks like eslint-linter-browserify isn't installed in the package.json? Would you be able to address this? Thanks!

[Nishthajain7]

The changes to package.json got lost when I discarded the old changes and force-pushed the new ones. I made the changes now

[khanniie]

Hi! Thanks for updating the package.json. I just checked out the branch but unfortunately it doesn't build for me. I get a Module not found: Can't resolve 'eslint-linter-browserify' in '/usr/src/app/client/modules/IDE/components/Editor' client/modules/IDE/components/Editor/stateUtils.js error. I looked into this a bit more and it actually looks like the import method needs to be following the example they gave in their Codemirror example here! https://github.com/UziTech/eslint-linter-browserify/blob/064fd06afd68555be7fccaea329182552a95beeb/example/script.js

It also looks like we wouldn't need to go through the trouble of parsing the message responses and could just pass the linter in directly, if you reference the example code linked above. Could you make the following changes? Thank you!

[Nishthajain7]

@khanniie Thank you for your guidance and suggestions. I've made the requested changes and now it looks much more simpler. I have tested the build as well and it works. Sorry for the inconvinience caused.