build!: migrate to type: "module" (WIP)

[toyobayashi]

Although I think node16 not respecting __esModule makes the interoperability of ESM and CJS quite messy between runtime and bundler / TypeScript Compiler, it is undeniable that the community will continue move forward.

• https://antfu.me/posts/move-on-to-esm-only
• module: implement the "module-sync" exports condition nodejs/node#54648

This PR changes the bundled files of emnapi packages to

dist/[name].js
    ESM for bundlers and Node.js, may contain `process.env.NODE_ENV` and external `import`

dist/[name].cjs
    CJS for bundlers and Node.js may contain `process.env.NODE_ENV` and external `require`

dist/[name].umd.cjs
    UMD for `<script>`, evaluate `process.env.NODE_ENV = false` at build time, all dependencies bundled

dist/[name].umd.min.cjs
    UMD for `<script>`, evaluate `process.env.NODE_ENV = true` at build time, all dependencies bundled

dist/[name].browser.js
    ESM for `<script type="module">`, evaluate `process.env.NODE_ENV = false` at build time, all dependencies bundled

dist/[name].browser.min.js
    ESM for `<script type="module">`, evaluate `process.env.NODE_ENV = true` at build time, all dependencies bundled

If runtime doesn't recognize module-sync condition, default resolve to CJS no matter using import or require to avoid dual-package hazard.

{
  "type": "module",
  "main": "./dist/[name].cjs",
  "module": "./dist/[name].js",
  "types": "./dist/[name].d.ts",
  "exports": {
    ".": {
      "types": {
        "module": "./dist/[name].d.ts",
        "module-sync": "./dist/[name].d.ts",
        "import": "./dist/[name].d.cts",
        "require": "./dist/[name].d.cts",
        "default": "./dist/[name].d.cts"
      },
      "module": "./dist/[name].js",
      "module-sync": "./dist/[name].js",
      "default": "./dist/[name].cjs"
    }
  }
}

When ESM becomes large enough in the community, I will migrate it to a pure ESM package.