Project restructuring (fixes macOS builds) (#198)

- Create `Include/` folder for all main projects
- Fix some issues here and there (found while moving things)
- All includes are now in `Tactility/` subfolder and must be included with that prefix. This fixes issues with clashing POSIX headers (e.g. `<semaphore.h>` versus Tactility's `Semaphore.h`)

Tactility/Source/app/imageviewer/ImageViewer.cpp

@@ -1,9 +1,11 @@
-#include <TactilityCore.h>
-#include "lvgl.h"
-#include "lvgl/Style.h"
-#include "lvgl/Toolbar.h"
-#include "StringUtils.h"
-#include "service/loader/Loader.h"
+#include "Tactility/lvgl/Style.h"
+#include "Tactility/lvgl/Toolbar.h"
+#include "Tactility/service/loader/Loader.h"
+
+#include <Tactility/TactilityCore.h>
+#include <Tactility/StringUtils.h>
+
+#include <lvgl.h>
 
 namespace tt::app::imageviewer {