Replace systemd-boot with GRUB for x64 UEFI boot mode
We are already using GRUB for IA32 so using GRUB for x64 will remove some bloat by removing some copies of initramfs and vmlinuz in EFI partition.
Major changes:
- Add
*_uefi-x64.grub.*
functions to mkarchiso. - Existing
*_uefi-x64.systemd-boot.*
functions are preserved because*_uefi-ia32.grub.*
functions are currently using some of them. - Add x64 UEFI shell to releng grub.cfg.
Fixes #159 (closed), #63 (closed).
Edited by plain linen