The functionality of the ibft settings plugin is now handled by
nm-initrd-generator. There is no need for it anymore, drop it.
Note that ibft called iscsiadm, which requires CAP_SYS_ADMIN to work
([1]). We really want to drop this capability, so the current solution
of a settings plugin (as it is implemented) is wrong. The solution
instead is nm-initrd-generator.
Also, on Fedora the ibft was disabled and probably on most other
distributions as well. This was only used on RHEL.
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1371201#c7
74641be816