Remove webpack build, bundle nanoid

[cp2004]

This plugin uses nanoid (possibly unnecessarily?), with import { nanoid } ..., and bundles this with webpack.

I'm bored of seeing dependabot updates for all these dependencies, so I will delete the webpack build - it's not used for anything other than old-browser compatibility with babel.

To import nanoid into the browser as a dependency, could do it like this

<script type="module">
import { nanoid } from '.......static etc./nanoid.js'
</script>

Or just bin it entirely, depending on why it is needed.