added Exposure code, DS3231, SSD1306, interfaces, started with protocol buffers impl.

components/ena/Kconfig

@@ -14,6 +14,12 @@ menu "Exposure Notification API"
       help
         Defines the maximum number of TEKs to be stored. (Default 14 [14 * 144 => 14 days])
 
+    config ENA_STORAGE_EXPOSURE_INFORMATION_MAX
+      int "Max. exporure information"
+      default 500
+      help
+        Defines the maximum number of exposure information to be stored. (Default 500)
+
     config ENA_STORAGE_TEMP_BEACONS_MAX
       int "Max. temporary beacons"
       default 1000
@@ -81,5 +87,12 @@ menu "Exposure Notification API"
         Defines the TEK rolling period in 10 minute steps. (Default 144 => 24 hours)
   endmenu
 
+  menu "Miscellaneous"
+    config ENA_RAM
+      int "ENA RAM"
+      default 100000
+      help
+        RAM required for main task. (Default 100 KB)
+  endmenu
 
 endmenu