(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 estimation for this is fast but not very accurate, meaning we save
around 5-10% storage space. (We also don’t try other channel coupling
methods, but I am sceptical of how much benefit that actually provides.)
This encoder can handle all integer formats and sample rates, though
only two channels well. It uses fixed LPC and performs a
close-to-optimal parameter search on the LPC order and residual Rice
parameter, leading to decent compression already.
