Add debian docs

debian/cloud/docs/MOUNT_CLOUD_IMAGE_AARCH64.md

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+# Debian Cloud Images
+
+```
+curl -LO https://cloud.debian.org/images/cloud/bookworm/latest/SHA512SUMS
+curl -LO https://cloud.debian.org/images/cloud/bookworm/latest/debian-12-genericcloud-arm64.qcow2
+```
+
+## Loopback mount - requires converting qcow to raw
+
+Install required tools:
+
+```
+sudo apt update
+sudo apt install qemu-utils
+```
+
+If the image is in QCOW2 format, convert it to raw:
+
+```
+qemu-img convert \
+  -f qcow2 \
+  -O raw \
+  debian-12-genericcloud-arm64.qcow2 \
+  debian-12-genericcloud-arm64.raw
+```
+
+Find the offset of where the partition starts:
+
+```
+$ fdisk -l debian-12-genericcloud-arm64.raw 
+Disk debian-12-genericcloud-arm64.raw: 2 GiB, 2147483648 bytes, 4194304 sectors
+Units: sectors of 1 * 512 = 512 bytes
+Sector size (logical/physical): 512 bytes / 512 bytes
+I/O size (minimum/optimal): 512 bytes / 512 bytes
+Disklabel type: gpt
+Disk identifier: AA17B800-9DDD-174C-87FE-0BBA5A1FF598
+
+Device                              Start     End Sectors  Size Type
+debian-12-genericcloud-arm64.raw1  262144 4192255 3930112  1.9G Linux root
+debian-12-genericcloud-arm64.raw15   2048  262143  260096  127M EFI System
+
+Partition table entries are not in disk order.
+
+
+# Offset is the start number times the sector size (usually 512 bytes)
+$ echo $((262144 * 512))
+134217728
+
+# Mount the image
+sudo mkdir /mnt/debian-12
+sudo mount -o loop,offset=134217728 debian-12-genericcloud-arm64.raw /mnt/debian-12
+
+$ ls /mnt/debian-12/
+bin   dev  home  lost+found  mnt  proc  run   srv  tmp  var
+boot  etc  lib   media       opt  root  sbin  sys  usr
+
+# Unmount the image
+sudo umount /mnt/debian-12
+sudo rmdir /mnt/debian-12
+```
+
+## Mount cloud image with qemu-nbd
+
+```
+# Load the nbd module
+$ sudo modprobe -v nbd
+insmod /lib/modules/6.5.0-41-generic/kernel/drivers/block/nbd.ko
+# Verify the nbd module is loaded
+$ lsmod | grep nbd
+nbd                    65536  0
+
+$ ls /dev/nbd*
+/dev/nbd0   /dev/nbd11  /dev/nbd14  /dev/nbd3  /dev/nbd6  /dev/nbd9
+/dev/nbd1   /dev/nbd12  /dev/nbd15  /dev/nbd4  /dev/nbd7
+/dev/nbd10  /dev/nbd13  /dev/nbd2   /dev/nbd5  /dev/nbd8
+
+# Connect the QCOW2 image as a network block device
+$ sudo qemu-nbd --connect=/dev/nbd0 debian-12-genericcloud-arm64.qcow2
+
+# Create a mount point directory
+$ sudo mkdir /mnt/debian-12
+
+$ sudo fdisk -l /dev/nbd0
+Disk /dev/nbd0: 2 GiB, 2147483648 bytes, 4194304 sectors
+Units: sectors of 1 * 512 = 512 bytes
+Sector size (logical/physical): 512 bytes / 512 bytes
+I/O size (minimum/optimal): 512 bytes / 512 bytes
+Disklabel type: gpt
+Disk identifier: AA17B800-9DDD-174C-87FE-0BBA5A1FF598
+
+Device        Start     End Sectors  Size Type
+/dev/nbd0p1  262144 4192255 3930112  1.9G Linux root (ARM-64)
+/dev/nbd0p15   2048  262143  260096  127M EFI System
+
+Partition table entries are not in disk order.
+
+
+
+```