This generates grub efi application images for multiple archs, and
allows installing a grub efi image on a host with a different arch (e.g.
x86 efi app on x86_64 system)
I'm pretty sure that using arch="any", etc is not the best way to package this, so I'm open to suggestions.
Also, maybe something like this would fit better in Alpine, but I wanted to make the MR here so we can discuss it more.
I'm not happy with how deviceinfo vars for boot stuff have been handled (using generate in the name for those vars is kinda misleading, imho). I would much rather use some format for those vars like: deviceinfo_<bootloader>_<bootloader-specific config used by bootdeploy>, and so I used new vars with this format in both the patch here, the changes in boot-deploy, and the patch in pmbootstrap that I'll submit on the mailing list shortly.
The motivation for this is to simplify how pmOS configures x86 and x86_64 systems that use EFI boot. With this change, device packages will no longer need to provide a grub.cfg, or generate a grub EFI app image. boot-deploy is able to also properly inject kernel cmdline params from deviceinfo too (currently device packages that provide a grub.cfg are hard-coding kernel cmdline params...)
