[Feature Request] Default preset

It would be nice if there were a way to specify a default preset so every import didn't need the query string.

Maybe something like this...
```js
imagePresets({
'default': widthPreset({
widths: [425, 1024, 1200],
formats: {
webp: { quality: 100 },
png: { quality: 100 }
}
})
}),
```

Or this...
```js
imagePresets({
'foobar': widthPreset({
default: true,
widths: [425, 1024, 1200],
formats: {
webp: { quality: 100 },
png: { quality: 100 }
}
})
}),
```

Great plugin btw 👍 It's saved me a lot of time already.

Start by locating the imagePresets configuration and the handling of imports that include a query string. Compare the two proposed default-preset approaches and define how an import without a query should select the default; done means such imports use the configured preset while explicit query strings continue to work.

Written by the indexing model from the issue text.