prop140/compression: Refactor directory cache spooling code
Our current logic for spooling things from a directory server is a bit loopy. Instead we should refactor it so that "things to be spooled" is a first-class object, with implementations depending on what we're spooling. This will make lots of our directory improvement stuff easier to implement.
To upload designs, you'll need to enable LFS and have admin enable hashed storage. More information