Use heap_4.c FreeRTOS implementation

Implement storage HAL for STM32

Fix definition of CREATE_TASK() macro

Reduce configMINIMAL_STACK_SIZE on STM32

Fix warning in printf()

Fix all warnings triggered by -Wsign-compare

Use CREATE_TASK() macro for creating the SX127X task

Correctly handle per slave SPI clock and mode

Implement serial layer for STM32

Prepend current millis() to log statements

Fix debug builds on STM32

Split configuration into common, TX and RX specific

Rename tx_pin and rx_pin in serial_port_config_t

Add conveniency stlink-flash target

Don't send p2p pings on platforms without P2P