Update Azure release bits

Imports the changes for building official images on Azure Marketplace,
which fulfill the requirements of Azure and FreeBSD cloud images like
disk layout and UEFI for Gen2 VM, along with some minor improvements like
configurations to speed up booting.

"CLOUDWARE" list will be updated after some more collaborations with re
completed.

Reviewed by: re (gjb)
Sponsored by: The FreeBSD Foundation
Technical assistance from: Microsoft
Differential Revision: https://reviews.freebsd.org/D23804