Application example with mcci-catena/arduino-lmic on STM32L071

[Ludwig]

@bluejedi

I use the following workaround to fix the timing issue experienced with downlinks

@bluejedi

When using this workaround with MCCI LMIC I ran into certain issues that I have not yet further investigated.

If using the newer MCCI version, be aware that the maximum clock error is limited to 0.4% if the LMIC_ENABLE_arbitrary_clock_error is not defined. See also arduino-lmic/README.md at master · mcci-catena/arduino-lmic · GitHub.
With the STM32L071 running from the 16MHz HSI a clock error setting of 0.4% works for me. Though I have not tested at highest or lowest expected temperatures yet, which will have an effect on clock drift.