Add LoRa support to the Elf

[stfu-donny]

The issue

LoRa is quickly becoming the de-facto communication standard for IoT devices. Because it allows for communication over greater distances and uses less power than WiFi, it would be a very good feature for the Elf to possess. This is especially true if you wanted the Elf running in a remote location with limited power capabilities.

Main Goals

• Establish a test point-to-point LoRa connection
• Build a gateway device
• Send collected data to the gateway
• Have the gateway registered on TTN

[layerzerolabs]

Great stuff! Tiny point - can you add the labels waterelf32 and enhancement please (helps me keep track)?