Add support for Jetson Orin NX

[Austriker]

Enable support for a jetson Orin NX with NVMe

Based on this issue: https://hub.mender.io/t/jetson-orin-nx-and-jetpack-6-mender-intergration-issues/7375

• Create custom partition layout
• Use <allocation_attribute> 0x808 </allocation_attribute> to expand the user partition automatically during the flash process
• Add documentation

[TheYoctoJester]

Hi @Austriker,

As you mentioned on IRC, I think changing to

PARTITION_FILE_EXTERNAL:p3768-0000-p3767-0000 = "${WORKDIR}/flash_l4t_t234_nvme_rootfs_ab.xml"

is a good approach. However it has the small shortcoming being tied to exactly this machine. So how about adding a short note to the layers README which explains why the line is there, and hints at adapting it for custom Orin NX based machines?

[Austriker]

Hi @TheYoctoJester ,

I fixed the PR and added some documentation. I also remove the quick start guide since for me mender integration is not maintained anymore in tegrademo-distro.