docs: update cli reference

Signed-off-by: Adphi <philippe.adrien.nousse@gmail.com>

docs/content/reference/d2vm_build.md

@@ -0,0 +1,33 @@
+## d2vm build
+
+Build a vm image from Dockerfile
+
+```
+d2vm build [context directory] [flags]
+```
+
+### Options
+
+```
+      --append-to-cmdline string   Extra kernel cmdline arguments to append to the generated one
+      --build-arg stringArray      Set build-time variables
+  -f, --file string                Name of the Dockerfile
+      --force                      Override output image
+  -h, --help                       help for build
+      --network-manager string     Network manager to use for the image: none, netplan, ifupdown
+  -o, --output string              The output image, the extension determine the image format, raw will be used if none. Supported formats: qcow2 qed raw vdi vhd vmdk (default "disk0.qcow2")
+  -p, --password string            Root user password (default "root")
+      --raw                        Just convert the container to virtual machine image without installing anything more
+  -s, --size string                The output image size (default "10G")
+```
+
+### Options inherited from parent commands
+
+```
+  -v, --verbose   Enable Verbose output
+```
+
+### SEE ALSO
+
+* [d2vm](d2vm.md)	 - 
+