Add LORA gateway

first implementation of a lora gateway integration, tested on ttgo heltec boards with embedded lora module #356
Sending and receiving working

lib/arduino-LoRa/library.properties

@@ -0,0 +1,10 @@
+name=LoRa
+version=0.5.0
+author=Sandeep Mistry <sandeep.mistry@gmail.com>
+maintainer=Sandeep Mistry <sandeep.mistry@gmail.com>
+sentence=An Arduino library for sending and receiving data using LoRa radios.
+paragraph=Supports Semtech SX1276/77/78/79 based boards/shields.
+category=Communication
+url=https://github.com/sandeepmistry/arduino-LoRa
+architectures=*
+includes=LoRa.h