tailwind.config.js not generated

when you create your site, there is no generation of the tailwind config file.

This needs to be created by the user.

Here are some things that could be done to improve this:

## Create the template on run if not exists
We could create the basic config as a template

```js
/** @type {import('tailwindcss').Config} */
module.exports = {
content: ['output/**/*.{html, js}'],
plugins: [require('@tailwindcss/typography')] // This could be optional as a plugin_extra
}
```

We can then have a `pre_build_site` hookspec that happens prior to rendering that checks for the `tailwind.config.js` and creates the file if it doesn't exist.

```python
import pathlib

class TailwindCSS:

@hook_impl
def pre_build_site(site:Site):
if not pathlib.Path('tailwind.confilg.js').exits():
Template(tailwind_config_template).render(extras=extras)
```

Start by locating the TailwindCSS plugin entry point and checking whether a pre_build_site hook or template mechanism already exists. Confirm how extras and generated files are handled, then verify that a basic tailwind.config.js is created before rendering only when the file is absent.

Written by the indexing model from the issue text.