pigpio: new package

pigpio: new package

Pigpio is a library for the Raspberry Pi which allows
control of the General Purpose Input Outputs (GPIO).

http://abyz.me.uk/rpi/pigpio/

Signed-off-by: Grzegorz Blach <grzegorz@blach.pl>
[Thomas:
 - Use proper SPDX tag for The Unlicense
 - Add missing dependency on !BR2_STATIC_LIBS, since the Makefile is
   unconditionally building a shared library
 - Use BR2_arm instead of BR2_ARM_EABIHF, there's nothing that makes
   it EABIHF specific.
 - Use -D and full destination paths during the installation.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>