Add documentation of adapting old watchfaces to work

doc/watchfaces.md

@@ -0,0 +1,54 @@
+# Adapting old watchfaces:
+ - When resolving conflicts, delete clock.h/.cpp, keep both in CMakeLists.cpp, accept current in SettingWatchFace.cpp, and keep both if there are any changes in fonts.
+ - Add entry to WatchFace enum in displayapp/apps/Apps.h.in
+ - Remove `DisplayApp* app` param from constructor in .h and .cpp and remove Screen(app) from initializer list on constructor in .cpp
+ - Add const to batteryController and bleController is present in constructor params and in private members in .h
+ - In .cpp, remove `#include <date/date.h>` and convert calls to get time to format like in working watch faces. For example:
+```cpp
+    auto newDateTime = currentDateTime.Get();
+
+    auto dp = date::floor<date::days>(newDateTime);
+    auto time = date::make_time(newDateTime - dp);
+
+    uint8_t hour = time.hours().count();
+    uint8_t minute = time.minutes().count();
+```
+with
+```cpp
+    uint8_t hour = dateTimeController.Hours();
+    uint8_t minute = dateTimeController.Minutes();
+```
+, add 
+```cpp
+Utility::DirtyValue<std::chrono::time_point<std::chrono::system_clock, std::chrono::days>> currentDate;
+```
+to .h
+ - Remove `motionSensorOk = motionController.IsSensorOk();` and reference to `motionSensorOk` in following if
+ - In .h add `#include "utility/DirtyValue.h"` and replace all `DirtyValue<>` vars with `Utility::DirtyValue<>`
+ - Add WatchFaceTraits:
+ ``` cpp
+     template <>
+    struct WatchFaceTraits<WatchFace::Digital> {
+      static constexpr WatchFace watchFace = WatchFace::Digital;
+      static constexpr const char* name = "Digital face";
+
+      static Screens::Screen* Create(AppControllers& controllers) {
+        return new Screens::WatchFaceDigital(controllers.dateTimeController,
+                                             controllers.batteryController,
+                                             controllers.bleController,
+                                             controllers.notificationManager,
+                                             controllers.settingsController,
+                                             controllers.heartRateController,
+                                             controllers.motionController,                                             controllers.filesystem
+                                             *controllers.weatherController);
+      };
+  
+
+      static bool IsAvailable(Pinetime::Controllers::FS& filesystem) {
+        return Screens::WatchFaceCasioStyleG7710::IsAvailable(filesystem);
+      }
+    };
+```
+modify as necesary.
+- Add include to UserApps.h: `#include "displayapp/screens/WatchFace---.h"`
+- Add to displayapp/apps/CMakeLists.txt