Puts back the restriction on greyscale config location so that all the
configs have to be in the same overall place. Having all the configs in
a single folder *is* a mess, but this is why subfolders exist. Having
configs scattered throughout the code folder would make it a pain to
keep track of all the different configs, especially when it comes time
for breaking changes. The config folder should be thought of similarly
to the icons folder.
Put your configs in subfolders meant for their type, and make new ones
if it seems appropriate just like how we do with icons.
6dd42926c7