feat: preserve module structure to improve tree-shaking (#1783)

* perf: preserve module structure to improve tree-shaking + other improvements

- Replace `rollup-plugin-license` with Rollup’s built-in `option.banner`
- Slightly speed up Babel transpilation by targeting `tsx?` files first.

* build(babel): simplify config, build for modern browsers

* build(browserslist): expand modern browser support, drop rare mobile browsers

* build(all components): point pkg.json `module` field to `dist/esm/index.js`

* chore: remove unused Babel + Rollup plugins

Author: ze-flo

babel.config.js

@@ -10,19 +10,19 @@ module.exports = {
     [
       '@babel/preset-env',
       {
-        targets: '> 0.5%, last 2 versions, Firefox ESR, not dead'
+        // https://browsersl.ist/#q=%3E+0.3%25%2C+last+2+versions%2C+Firefox+ESR%2C+not+dead%2C+not+and_qq+13-14%2C+not+kaios+2-5
+        targets: '> 0.3%, last 2 versions, Firefox ESR, not dead, not and_qq 13-14, not kaios 2-5'
+      }
+    ],
+    [
+      '@babel/preset-react',
+      {
+        useBuiltIns: true // https://babeljs.io/docs/babel-preset-react#usebuiltins
       }
     ],
-    '@babel/preset-react',
     ['@babel/preset-typescript', { onlyRemoveTypeImports: true }]
   ],
-  plugins: [
-    '@babel/plugin-transform-object-assign',
-    ['@babel/plugin-transform-class-properties', { loose: true }],
-    'babel-plugin-styled-components',
-    ['@babel/plugin-transform-private-property-in-object', { loose: true }],
-    ['@babel/plugin-transform-private-methods', { loose: true }]
-  ],
+  plugins: ['babel-plugin-styled-components'],
   env: {
     production: {
       plugins: [['react-remove-properties', { properties: [/data-test/u] }]]