Add position prop to support all Builder params

[thomkrupa]

Hey,

First of all, fantastic work on the unpic library.

I would love to have option to set position param, it's especially useful for setting better crop.

https://www.builder.io/c/docs/image-api

Thanks!

[thomkrupa]

Can you support more params? We deliberately just support the most common params that are shared between all CDNs. If you need more params then you can use the CDN-specific API directly.

I think position/crop is a pretty important prop, but I think is ok not to add it as official prop to keep the base simple.

@ascorbic what about a good way to extend props/add customs for transformers? Currently it's not that obvious. Something like:

const url = transformUrl(
  {
    URL: "...",
    width: 800,
    height: 600,
    cdn: "builder",
    customSearchParams: {
       position: "left top"
    }
  },
);

Right now, I pass those custom params to the URL, like this:

<Image src={imageSrc + "?position=left%20top"} />

It works. I know I can build a custom component for this, but it would be cool if the official component could look like this:

<Image
  src={imageSrc}
  customSearchParams={{
    position: "left top"
  }}
/>