eal/windows: add interrupt thread skeleton

eal/windows: add interrupt thread skeleton

Windows interrupt support is based on IO completion ports (IOCP).
Interrupt thread would send the devices requests to notify about
interrupts and then wait for any request completion. Add skeleton code
of this model without any hardware support.

Another way to wake up the interrupt thread is APC (asynchronous procedure
call), scheduled by any other thread via eal_intr_thread_schedule().
This internal API is intended for alarm implementation.

Signed-off-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
Acked-by: Narcisa Vasile <navasile@linux.microsoft.com>