add basic metronome app (#409)

* add basic metronome app

* add bpb, tap to bpm, update widgets

* use event pressed for bpm tap

* move case statement break to the right place

* narrow bpm selection range, override touch events

* fix arc knob style

* re-enable sleeping in destructor

src/displayapp/screens/Metronome.h

@@ -0,0 +1,34 @@
+#pragma once
+
+#include "systemtask/SystemTask.h"
+#include "components/motor/MotorController.h"
+
+#include <array>
+
+namespace Pinetime::Applications::Screens {
+
+  class Metronome : public Screen {
+  public:
+    Metronome(DisplayApp* app, Controllers::MotorController& motorController, System::SystemTask& systemTask);
+    ~Metronome() override;
+    bool Refresh() override;
+    bool OnTouchEvent(TouchEvents event) override;
+    void OnEvent(lv_obj_t* obj, lv_event_t event);
+    enum class States { Running, Stopped };
+
+  private:
+    bool running;
+    States currentState;
+    TickType_t startTime;
+    TickType_t tappedTime = 0;
+    Controllers::MotorController& motorController;
+    System::SystemTask& systemTask;
+    uint16_t bpm = 120;
+    uint8_t bpb = 4;
+    uint8_t counter = 1;
+
+    lv_obj_t *bpmArc, *bpmTap, *bpmValue, *bpmLegend;
+    lv_obj_t *bpbDropdown, *bpbLegend;
+    lv_obj_t *playPause, *playPauseLabel;
+  };
+}