Persist bond between reboots

Save bond information in the FS after a disconnect or encryption change
if the bond is not already stored. The bond is restored on boot enabling
automatic reconnection to a previously bonded central.

Two consecutive watch reboots with the central out of range (or BLE off)
will remove the stored bond from the watch.

src/systemtask/SystemTask.cpp

@@ -109,7 +109,8 @@ SystemTask::SystemTask(Drivers::SpiMaster& spi,
                      batteryController,
                      spiNorFlash,
                      heartRateController,
-                     motionController) {
+                     motionController,
+                     fs) {
 }
 
 void SystemTask::Start() {