udev: ata_id: log faling ioctls as "debug"
machinectl: privileged option is gone
udev: link-config - let udevd set the ifname
udev: link-config - less verbose logging

Also reinstate print to kmsg when renaming netif.
libudev: default log_priority to INFO

This brings it in sync with the default config file.
bus: move ssh support into public API of libsystem-bus
bus: add API call to create bus connection to the system bus of local containers

Also, add support for this to machinectl, so that we can enumerate the
machines that run inside a container. We must go deeper!
machinectl: we don't really just show information, we execute operations
udev: config-link - one less log_info
udev: rules - move parsing error to log_error()
link-config: support --enable-split-usr
timedated: support --enable-split-usr
general: various cleanups
run: add support for executing commands remotely via SSH or in a container

Also, unify the transport logic a bit, since we reuse the same scheme in
many of our client tools.
util: when we use path_strv_canonicalize() we must allocate the strv from the heap
nspawn: only pass in slice setting if it is set
timedatectl: port to sd-bus
localectl: port to libsystemd-bus
localectl: remove unused 'P' arg
bus-util: avoid infinite loop