Catch the EFI loader up to the latest ZFS Boot Environment Menu features

MFC: r294072
Move init_zfs_bootenv to sys/boot/zfs/zfs.c instead of having a copy in each loader

MFC: r294073
Connect the ZFS boot environment menu to the UEFI loader

MFC: r295357
Do not set vfs.root.mountfrom unnecessarily when initializing ZFS BE menu

Approved by: re (marius)
Relnotes: yes
Sponsored by: ScaleEngine Inc.

MFC: r293001
Introduce the ZFS Boot Environments menu to the loader menu

MFC: r293414
Add ZFS Boot Environments menu to userboot

MFC: r293454
Only call init_zfs_bootenv when the system is booted with ZFS

MFC: r293612
Fix calling init_zfs_bootenv to early, resulting in empty ZFS BE menu

Relnotes: yes
Sponsored by: ScaleEngine Inc.

MFC: r277949:
New function smbios_match to detect BIOS versions during boot

MFC: r277957:
Fix order of functions in smbios.c (corrects r277949)

MFC: r281138:
SMBIOS support for EFI

r281138 makes changes to the new unified EFI loader (r280950), which has not been merged to stable/10 (and likely won't be).
These changes were manually applied to the amd64 EFI loader (sys/boot/amd64/efi).
The changes to sys/boot/amd64/efi are a direct commit.

Reviewed by: stas
Approved by: re (gjb), marcel
Sponsored by: ScaleEngine Inc.
Differential Revision: https://reviews.freebsd.org/D3129

MFC: r277949:
New function smbios_match to detect BIOS versions during boot

MFC: r277957:
Fix order of functions in smbios.c (corrects r277949)

MFC: r281138:
SMBIOS support for EFI

r281138 makes changes to the new unified EFI loader (r280950), which has not been merged to stable/10 (and likely won't be).
These changes were manually applied to the amd64 EFI loader (sys/boot/amd64/efi).
The changes to sys/boot/amd64/efi are a direct commit.

Reviewed by: stas
Approved by: re (gjb), marcel
Sponsored by: ScaleEngine Inc.
Differential Revision: https://reviews.freebsd.org/D3129