feat: modify pienapple-picture with my remix

- change UI layout to make it looks like the default style of Windows image browser.
- update icons to material design icon for better looks. add lost icons for those new added button at the bottom bar.
- restore window style to normal. remove borderless style.
- delete X button at the right-top corner. disable feature that drag window to move, because all functions provided by native window are restored.
- move prev next image button to the center of bottom bar.
- move navigator view to the right-bottom corner so that it will not overlay on the shown image.
- remove all animation effect, including alpha transition, fade out when exiting and etc.
- delete function that double click windows to exit. now double clicking windows will do nothing. change default value of double click behavior to do nothing.
- change default value of stay on top to false because stay on top is not the default behavior of Windows image browser.

app/graphicsview.cpp

@@ -22,8 +22,7 @@ GraphicsView::GraphicsView(QWidget *parent)
     setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
     setResizeAnchor(QGraphicsView::AnchorUnderMouse);
     setTransformationAnchor(QGraphicsView::AnchorUnderMouse);
-    setStyleSheet("background-color: rgba(0, 0, 0, 220);"
-                  "border-radius: 3px;");
+    setStyleSheet("border-style: none;");
     setAcceptDrops(false);
     setCheckerboardEnabled(false);