This simply implements listAllNodeDevices using helper virNodeDeviceList

src/node_device/node_device_driver.h:
  * Declare nodeListAllNodeDevices.

src/node_device/node_device_driver.c:
  * Implement nodeListAllNodeDevices.

src/node_device/node_device_hal.c:
  * Hook listAllNodeDevices to nodeListAllNodeDevices.

src/node_device/node_device_udev.c
  * Hook listAllNodeDevices to nodeListAllNodeDevices.