Gui: Add a separate checkbox for enabling spinning animations (#11534)

* Gui: Create group box for animation preferences

* Gui: Add spinning animation checkbox

* Gui: Implement isAnimating() for NavigationAnimator

* Gui: No need to enable animations in DemoMode

The spin animation is played regardless of the user preference and does not need to be enabled before starting the spin animation

* Gui: Change comment

src/Gui/NavigationAnimator.cpp

@@ -90,3 +90,15 @@ void NavigationAnimator::stop()
         activeAnimation.reset();
     }
 }
+
+/**
+ * @return Whether or not an animation is active
+ */
+bool NavigationAnimator::isAnimating() const
+{
+    if (activeAnimation != nullptr) {
+        return activeAnimation->state() == QAbstractAnimation::State::Running;
+    }
+
+    return false;
+}