Webpack plugin for better DX

## Proposal

Need implement webpack plugin for better DX:

1. Not run manually builds tokens
2. Not storage locally result **css** files

## Use case

```js
module.exports = {
plugins: [
new ThemekitWebpackPlugin({ ... }),
]
}
```

No files or tests are named. Start by tracing the repository's existing design-token build flow and how a webpack plugin would fit the shown configuration; done means builds no longer need to be run manually and generated CSS results are not stored locally.

Written by the indexing model from the issue text.