While it's nice to see <img src="foo.svg"> suddenly work in Ladybird
after linking with the Qt SVG module, this is cheating.
We should implement SVG-as-image ourselves instead of relying on 3rd
party code to do it. :^)
Because TGA images don't have magic bytes as a signature to be detected,
instead assume a sequence of ReadonlyBytes is a possible TGA image only
if we are given a path so we could check the extension of the file and
see if it's a TGA image.
When we know the path of the file being loaded, we will try to first
check its extension, and only if there's no match to a known decoder,
based on simple extension lookup, then we would probe for other formats
as usual with the normal sniffing method.
