Add support for systemd-boot

[allaeddineomc]

Is your feature request related to a problem? Please describe.
systemd bootctl is installed by default on fedora silverblue but using it doesn't work because it fails to detect ostree deployments , normally just using grub as a bootloader is fine but in cases where the user wants to dualboot silverblue with any other fedora variant grub will be overwritten by whatever os was the last to be installed/updated , another reason why the user might want to use systemd boot instead of grub is that systemd boot is much faster and simpler to configure , in my case grub is very buggy on my hardware and none of the bug reports i filled upstream were looked into

Describe the solution you'd like
adding rpm-ostree scripts to generate boot entries for systemd boot

Describe alternatives you've considered
adding support for any other fast and easy to install bootloader like syslinux ( definitely not rEFInd XD )
i think systemd boot is the best choice just because installing it won't require layering any additional packages

Additional context
Add any other context or screenshots about the feature request here.

[travier]

The currently recommended path for dual booting with Silverblue is to have 2 separated EFI partitions and to use the "second" one for Silverblue only, chain booting from the first one to the Silverblue one.

While rpm-ostree generates BLS configs, we don't support systemd-boot yet.

A dependency for this one is #120.

[allaeddineomc]

what are the components that i need to write patches for to get systemd boot working ?

[travier]

• systemd-boot support ostreedev/ostree#1719
• Provide a command line option to install systemd-boot rather than grub2 on x86_64 and arm64 rhinstaller/anaconda#4368
• Use bootupd and remove ostree-grub2 (was: All deployments are shown twice in grub) #120