Frame counter does not persist in ABP mode

Currently the RAK811 reset the frame counter to 0 when it reset .This causes ABP end nodes wouldn’t survive a reset or power loss as TTN would reject the uplink frames if the corresponding uplink frame counter is not reset manually on TTN. LoRaWAN 1.1 addresses this problem by adding this statement:

ABP devices have their Frame Counters initialized to 0 at fabrication. In ABP devices the frame counters MUST NEVER be reset during the device’s life time. If the end-device is susceptible of losing power during its life time (battery replacement for example), the frame counters SHALL persist during such event.