Candidates repos for archiving and removing due to license mismatch

[miao0miao]

• [ ] nomad has a license mismatch - https://github.com/flatcar/nomad-on-flatcar/issues/4
• [ ] Grub is archived and read-only - could it be removed and change to use an upstream source? https://github.com/flatcar/grub
• [ ] shim - https://github.com/flatcar/shim