mkosi-initrd: initial enablement for Tumbleweed

Hi! For those of you who want to experiment with an alternative initrd generator, I've prepared the initial enablement of mkosi-initrd for Tumbleweed. Why is it interesting and different from other initrd generators? Mainly, because it builds the initrd from distro packages instead of picking everything from your local host. Analysis and instructions: https://en.opensuse.org/Mkosi-initrd *A big warning here*: this is just a proof of concept, an incomplete initrd can break the system boot, so always keep a copy of a working image. Feedback is appreciated. Have fun! -- Antonio Álvarez Feijoo System Boot and Init SUSE