Add support for `carrier-wait-timeout` setting from kernel cmdline.
This will create a new `15-carrier-timeout.conf` file in
/run/NetworkManager/conf.d with the parameter value as specified.
The setting also inserts `match-device` to `*`, matching all devices.
NB: The parameter on kernel cmdline is specified in seconds. This is
done to be backwards compatible with with network-legacy module. However
the generated setting will automatically multiply specified value by
1000 and store timeout value in ms.
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/issues/626https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/730
nm-initrd-generator scans the command line for options relevant to network
configuration and creates configuration files for an early instance of
NetworkManager run from the initial ramdisk during early boot.
