feat!: move to ESM first with dual esm/cjs package exports

[userquin]

Description

This PR includes:

• move to ESM first (type module)
• removes the postbuild script, using default output from tsup seem to be ok (without cjsInterop): updating to tsup 8 may require some changes
• use import and require in package exports (removed types)

Linked Issues

Additional context

Current types (check https://arethetypeswrong.github.io/?p=unplugin-vue-components%400.25.2 or https://publint.dev/unplugin-vue-components@0.25.2):

With this PR:

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[userquin]

rspack and esbuild tested in my local, check https://github.com/unplugin/unplugin-auto-import/pull/453#issuecomment-1837183563 and https://github.com/unplugin/unplugin-auto-import/pull/453#issuecomment-1837179525 respectively