feat: add netvm shell for raw shel access

src/host/rootfs/usr/local/bin/netvm

@@ -70,6 +70,19 @@ qga() {
 	fi
 }
 
+function cmd_shell(){
+        qemu-system-x86_64 \
+		-m 512M \
+		--machine q35 \
+		-nographic \
+		-net none \
+		-cdrom /guest.img \
+		-boot order=d \
+		-device qemu-xhci \
+		-device virtio-serial \
+		-device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0
+}
+
 function cmd_start(){
         [ ! -f "${LOCKFILE}" ] || { echo "Error: Netvm already running"; exit 1; }
 	local net_args=""
@@ -235,6 +248,8 @@ cmd_usage() {
 	      Start headless network vm in the background
 	  netvm stop
 	      Stop headless network vm
+	  netvm shell
+	      Start interactive network vm in the foreground
 	  netvm status
 	      Get hostname and uptime from running network vm
 	  netvm push <local-path> <remote-path>