naming.md: Added rule to use lower case files and folders only
naming.md: Added rule to use lower case files and folders only

Currently files and folders are all lower case.  Doxygen also
has a tag set to disallow files and folders with upper case
names.  Added an item on the naming.md page which states
only lower case names should be used for files and folders.

Signed-off-by: John Van Drasek <514c174da16cb65a89688761b233d923b6282d4d@intel.com>

skiselev/upm,whbruce/upm,skiselev/upm,andreivasiliu2211/upm,arfoll/upm,tylergibson/upm,Jon-ICS/upm,Propanu/upm,tripzero/upm,jontrulson/upm,yoyojacky/upm,noahchense/upm,Propanu/upm,MakerCollider/upm,afmckinney/upm,Vaghesh/upm,jontrulson/upm,malikabhi05/upm,tylergibson/upm,GSmurf/upm,arfoll/upm,afmckinney/upm,spitfire88/upm,jontrulson/upm,g-vidal/upm,spitfire88/upm,Propanu/upm,sasmita/upm,afmckinney/upm,Jon-ICS/upm,srware/upm,malikabhi05/upm,srware/upm,mircea/upm,sasmita/upm,andreivasiliu2211/upm,spitfire88/upm,arfoll/upm,Jon-ICS/upm,intel-iot-devkit/upm,Propanu/upm,stefan-andritoiu/upm,intel-iot-devkit/upm,intel-iot-devkit/upm,stefan-andritoiu/upm,fieldhawker/upm,tripzero/upm,mircea/upm,ShawnHymel/upm,rafaneri/upm,yoyojacky/upm,stefan-andritoiu/upm,fieldhawker/upm,malikabhi05/upm,pylbert/upm,g-vidal/upm,pylbert/upm,whbruce/upm,rafaneri/upm,izard/upm,tylergibson/upm,tripzero/upm,stefan-andritoiu/upm,nitirohilla/upm,GSmurf/upm,kissbac/upm,intel-iot-devkit/upm,noahchense/upm,nitirohilla/upm,skiselev/upm,yoyojacky/upm,mircea/upm,mircea/upm,skiselev/upm,sasmita/upm,intel-iot-devkit/upm,srware/upm,afmckinney/upm,Propanu/upm,mircea/upm,izard/upm,arfoll/upm,kissbac/upm,Jon-ICS/upm,tripzero/upm,whbruce/upm,rafaneri/upm,pylbert/upm,andreivasiliu2211/upm,kissbac/upm,sasmita/upm,pylbert/upm,GSmurf/upm,nitirohilla/upm,intel-iot-devkit/upm,pylbert/upm,MakerCollider/upm,nitirohilla/upm,malikabhi05/upm,malikabhi05/upm,tripzero/upm,Vaghesh/upm,spitfire88/upm,noahchense/upm,skiselev/upm,tylergibson/upm,malikabhi05/upm,kissbac/upm,jontrulson/upm,Jon-ICS/upm,ShawnHymel/upm,tylergibson/upm,arfoll/upm,g-vidal/upm,yoyojacky/upm,fieldhawker/upm,GSmurf/upm,Vaghesh/upm,whbruce/upm,g-vidal/upm,nitirohilla/upm,g-vidal/upm,MakerCollider/upm,kissbac/upm,MakerCollider/upm,noahchense/upm,sasmita/upm,andreivasiliu2211/upm,skiselev/upm,pylbert/upm,srware/upm,afmckinney/upm,jontrulson/upm,stefan-andritoiu/upm,Propanu/upm,Vaghesh/upm,yoyojacky/upm,andreivasiliu2211/upm,MakerCollider/upm,ShawnHymel/upm,whbruce/upm,ShawnHymel/upm,fieldhawker/upm,g-vidal/upm,spitfire88/upm,ShawnHymel/upm,izard/upm,rafaneri/upm,stefan-andritoiu/upm,rafaneri/upm,srware/upm