How to handle "nested" artifacts (PXE needs one deeper layer of extraction (kernel,...))

[pnpavlov]

How to handle "nested" artifacts (PXE needs one deeper layer of extraction (kernel,...))

Detection: match on *.pxe.tar.gz files
Consequence: Extraction of the pxe.tar.gz file, this leads to four additional files (tested once with amd64 and arm64 with the 1592.1 release of metal-gardener_prod_pxe):

- vmlinuz
- initrd
- root.squashfs
- boot.efi

Define media-types for those. The rest of the program logic will stay the same