Range header cannot be used by browsers

[achingbrain]

The IPFS HTTP Gateway specs make reference to the Range header - using this from browsers is hard since headers can't be specified in hyperlinks or typed into the address bar.

There is a similar entity-bytes query param exists but it only works with format=car.

If Range is a useful header we should add a range=... param that can be used to override the header value in a similar way to format and Accept.