feat: Add Secure Boot Support and Remove Grub Entry for Test this Media

[noelmiller]

Purpose

The purpose of this PR is to add secure boot support and remove the grub entry that does not currently work for the ISO installer. These were the last 2 items that needed to be fixed before we consider our ISOs good to ship. We are fast tracking this change in order to make sure we are ready for upcoming conferences (KubeCon and SCALE)

What was done

Secure Boot Support

Secure boot support is using the method we previously used in our old Isogenerator to enable secure boot support. This imports our key on the users system on first boot if secure boot is detected and opens mokutil to walk the user through importing it.

Removing Grub Entry

Current method for fixing this is by removing the entry in the template config file for both grub2-bios.cfg and grub2-efi.cfg using sed command. There is probably a way to override the config file, but this will work for now.

Conclusion

With these final 2 issues sorted out, I feel comfortable with shipping the new ISOs for Bluefin and Bazzite. We will come back to optimize at a later date.

[KyleGospo]

Looks good to me, secure boot fix is 100% proper and while the testing fix could be better, I think the sed command works fine as a patch and I'd rather it not be shown than be shown and lie about the status of the check.

[bigpod98]

having both secure boot and better grub experiance is important, Everything appears to be OK

[bsherman]

I downloaded and tested the generated test ISO for Fedora 38.

I confirm:

• the grub menu entry for ISO validation was removed
• the secure boot MOK import works and after install the user boots direct to the MOK UEFI tool

Looks good!