modules configuration is very confusing. Could it be simplified?

I am using version 3.1.8 and had great trouble getting a css file to avoid getting hashed by the module code.

I have a `transition.css`.

My config was this:

```js
postcss({
extract: true,
modules: true,
use: ['sass'],
}),
```

I had to log this code to work it out even though I read #292 #296

```js
const autoModules = options.autoModules !== false && options.onlyModules !== true; // true
const isAutoModule = autoModules && isModuleFile(_this.id); // false
const supportModules = autoModules ? isAutoModule : options.modules; // finally false
```

I ended up eventually with this

```js
postcss({
extract: true,
modules: false,
autoModules: true,
use: ['sass'],
}),
```

It never occurred to me that modules: false would be the answer or autoModules would not apply to everything.

Should there not just be 1 boolean field and that is it? `{ modules: boolean }`

I don't know the history and apologies if this comes across rude as this is not my intent.