Support for Fedora Silverblue

[JaneSmith]

Would you be so kind as to add support for Fedora Silverblue?

I tried to set this up myself by modifying the Fedora configuration file, but for whatever reason the Fedora Silverblue installer would fail during its start-up sequence. Using the Fedora Silverblue image directly with the Fedora Media Writer worked fine though, so it seems like the issue was specific to multibootusb or my configuration file. I'm not sure what's needed to get it to work right.