This replaces the unmaintained serde_cbor with serde_json in both
db and IPC contexts. It changes the database on disk format to align
better to how we structure values in memory making it faster to load
entries when they aren't cached. And this breaks down the horrible
ValueSet enum to dyn trait types, which has a huge performance
improvement to the server.
Fixes#180 - this adds an oddjobd style tasks daemon to the unix tools. This supports creation of home directories and the maintenance of alias symlinks to these allowing user renames. The tasks daemon is written to require root, but is seperate from the unixd daemon. Communication is via a root-only unix socket that the task daemon connects into to reduce the possibility of exploit.
Fixes#369 due to the changes to call_daemon_blocking
