🛠 Add `index.js` as ESM

[StewEucen]

Overview

• Add index.js as ESM

Spec

• exports

category	explain
core	Standard rules without old stylistic
stylistic	@stylistic/eslint-plugin
stylisticJs	@stylistic/eslint-plugin-js
stylisticPlus	@stylistic/eslint-plugin-plus
jest	eslint-plugin-jest
jsdoc	eslint-plugin-jsdoc

Naming category to disable core stylistic rules

• Candidates

  1. CoreStylisticMask
  2. KickOutCoreStylistic
  3. DisableCoreStylistic
  4. NullifyCoreStylistic

• Decide disableCoreStylistic

Tasks

• [x] Add test for index.js
• [x] Implement index.js as ESM