eal/windows: add dirent implementation

eal/windows: add dirent implementation

Adding dirent.h on Windows to support common code.
eal_common_options.c includes this file.

The original contribution is under MIT license.
https://github.com/tronkko/dirent

Signed-off-by: Antara Ganesh Kolar <antara.ganesh.kolar@intel.com>
Signed-off-by: Pallavi Kadam <pallavi.kadam@intel.com>
Reviewed-by: Ranjit Menon <ranjit.menon@intel.com>
Reviewed-by: Keith Wiles <keith.wiles@intel.com>
Reviewed-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
Tested-by: Narcisa Ana Maria Vasile <narcisa.vasile@microsoft.com>
Acked-by: Narcisa Ana Maria Vasile <narcisa.vasile@microsoft.com>