[MSPAINT] Make imageArea window-less (#5215)

- Move imageArea code into canvasWindow.
- Delete imgarea.cpp, imgarea.h, and imageArea.
- Add CCanvasWindow::ImageToCanvas and CCanvasWindow::CanvasToImage to convert the coordinates.
- Realize drawing of resizing image area.
CORE-18867

base/applications/mspaint/drawing.h

@@ -38,3 +38,5 @@ BOOL
 ColorKeyedMaskBlt(HDC hdcDest, int nXDest, int nYDest, int nWidth, int nHeight,
                   HDC hdcSrc, int nXSrc, int nYSrc, int nSrcWidth, int nSrcHeight,
                   HBITMAP hbmMask, COLORREF keyColor);
+
+void DrawXorRect(HDC hdc, const RECT *prc);