This commit changes how NM is started inside the initrd. Instead of running NM
in the special --configure-and-quit=initrd mode, which sets up network and
quits, start it as a daemon.
This has multiple advantages. First, we no longer need to run NM in a special
mode that requires additional code and maintenance. NetworkManager works
exactly as in the real root.
One problem of the current configure-and-quit approach is that once NM has
quit, dynamic addresses can expire if the initrd setup takes longer than the
DHCP lease interval or than the IPv6 address lifetime. Running NM as a service
solves this problem.
Now NM runs with D-Bus support and therefore its API can be used by other
modules. This open the possibility, for example, to integrate nm-cloud-setup to
automatically configure networking based on cloud metadata.
Use the NetworkManager-wait-online.service, ordered before
dracut-initqueue.service, to delay the initqueue until NM has terminated its
configuration.