Support wildcard types e.g. `image/*`

It would be very useful to be able to say "any kind of image is fine" with e.g. `image/*` as an allowed type, rather than having to list out every specific image format you want to expect.

For responsibility it should be documented as to be considered carefully, as e.g. `image/*` feels harmless as it's just image formats, but that includes `image/svg+xml` which can carry risks via XML external entity attacks, CSS exfiltration using fonts, scripts etc - so not just "an image"!)

To go along with it, it would probably also be useful to be able to negate MIME types, so you could say "all images, except..." e.g. `image/* !image/svg+xml` or similar so that it's possible to skip particular ones you're worried about without having to go back to listing out every other acceptable type.