(cherry picked from commit 229b64a4b723a391c21f247d72d78cd575ace6ff;
minorly amended to fix conflict in image.cpp due to serenity in the
meantime adding webp writing support, and due to changes in Android and
Vulkan-related files that serenity doesn't have)
The intention for this utility is to eventually become a general-purpose
multimedia conversion tool like ffmpeg (except probably not with as many
supported formats, stream mappings and filters). For now, we can not
write any video format so the added complexity is not necessary at the
moment.