feat(nodes): setting the fastest BLE advertising frequency to 1 minute instead of 2

This is motivated by the measure period by the css811 sensor, which is 1 minute and cannot be set to 2.
Hence, we adverstise every minute to avoid trashing half of the measurements

nodes/src/supervisor.c

@@ -1,6 +1,6 @@
 #include "supervisor.h"
 
-const int SLEEP_GRANULARITY = 2;                    // [min]
+const int SLEEP_GRANULARITY = 1;                    // [min]
 const int SLEEP_MIN_DURATION = SLEEP_GRANULARITY;   // [min]
 const int SLEEP_MAX_DURATION = 30;                  // [min]