kola: Add Ignition mkfs tests

[bgilbert]

coreos/mantle@6e9e49bb12aded829e3d2e5a4939a6ef2bcda069 removed kola tests for creating filesystems with Ignition. We should reinstate those tests, since there might be distro-specific problems with mkfs tools. For example, this would have caught RHBZ 1916382.

Potentially we could have a qemu-specific test which adds an additional disk and uses it to create one of each filesystem type. On other platforms we'd need one test per filesystem type.

[jlebon]

The root reprovisioning tests implicitly do test at least XFS and ext4. We should probably add a test for btrfs though. Basically similar to https://github.com/coreos/fedora-coreos-config/tree/testing-devel/tests/kola/root-reprovision/filesystem-only.