- add support for more attribute types
* networkd:
+ - make sure RTM_NEWLINK messages match both the ifname and kind when setting the ifindex of a netdev
- add more keys to [Route] and [Address] sections
- add support for more DHCPv4 options (and, longer term, other kinds of dynamic config)
- add proper initrd support (in particular generate .network/.link files based on /proc/cmdline)