lora/lora-sx127x-pycom: Add unified SX1272/SX1276 LoRa driver.

Add a LoRa radio driver that handles both SX1272 and SX1276
transceivers. The existing lora-sx127x package only supports
SX1276 (version register 0x12); this driver also handles SX1272
(version 0x22) with its different register layouts for bandwidth,
coding rate, CRC, and RSSI calculation.

Used by Pycom LoPy (SX1272) and LoPy4 (SX1276) boards as defined
in micropython/micropython#19026.

Signed-off-by: Danilo D <danilodt@gmail.com>

Author: ddtdanilo