arduino_101: add support for factory configuration

The factory defconfigs should be used to generate images
compatible with the factory settings and the bootloader that
comes with the Arduino 101.

When using those images, you will be able to keep the original
bootloader and flash the images using dfu-utils and there will
be no need for a JTAG adapter.

Jira: ZEP-219
Change-Id: I34b5e9ef73314f46b31086a772d94d3ddcc6c436
Signed-off-by: Anas Nashif <anas.nashif@intel.com>