Show COVID-19 exposure notification statistics

Based on !390 (merged)

Displays how many unique MACs (aka phones) which send exposure notifications have been seen during the last 100 seconds.

It tries to distinguish between Apple and Google devices based on a heuristic mentioned in https://github.com/znuh/microbit-corona-scanner. The user can choose if they want the LEDs and/or the vibration motor to show newly discovered MACs / exposure notifications.

Loosely based on:

• https://github.com/kauzu/CoronaAppDetector
• https://github.com/frankrieger/CoronaAppDetectorM5StickC
• https://github.com/znuh/microbit-corona-scanner

Most of the logic resides in a plain Python script and can be modified by the user as needed.

epicardium/ble/ble_main.c

@@ -79,8 +79,8 @@ typedef union
 /*! configurable parameters for advertising */
 static const appAdvCfg_t bleAdvCfg =
 {
-  {0,             0,              0},                  /*! Advertising durations in ms */
-  {500/0.625,     4000/0.625,     0}                   /*! Advertising intervals in 0.625 ms units */
+  {0,             0},                  /*! Advertising durations in ms */
+  {500/0.625,     0}                   /*! Advertising intervals in 0.625 ms units */
 };
 
 /*! configurable parameters for slave */