Move tooltip window hover detector to HToolTip

Having a HoverHandler covering the root ApplicationWindow causes
problems for some Qt Quick Controls with pen/touch, e.g. it's impossible
to focus a TextArea/TextField.

The HoverHandler is moved to HToolTip (since it's used for those),
targets the ApplicationWindow but is now only enabled while a tooltip is
visible.

src/gui/Base/HToolTip.qml

@@ -12,8 +12,6 @@ ToolTip {
     property alias label: label
     property alias backgroundColor: background.color
 
-    readonly property bool hideNow: ! window.hovered
-
 
     function instantShow(timeout=-1) {
         if (visible) return
@@ -58,8 +56,6 @@ ToolTip {
         HNumberAnimation { property: "opacity"; to: 0.0 }
     }
 
-    onHideNowChanged: if (visible && hideNow) toolTip.hide()
-
     TapHandler {
         onTapped: toolTip.hide()
     }
@@ -67,4 +63,10 @@ ToolTip {
     HoverHandler {
         onHoveredChanged: if (! hovered) toolTip.hide()
     }
+
+    HoverHandler {
+        target: mainUI
+        enabled: toolTip.visible
+        onHoveredChanged: if (toolTip.visible && ! hovered) toolTip.hide()
+    }
 }

src/gui/Window.qml

@@ -10,7 +10,6 @@ ApplicationWindow {
 
     // FIXME: Qt 5.13.1 bug, this randomly stops updating after the cursor
     // leaves the window until it's clicked again.
-    readonly property alias hovered: windowHover.hovered
 
     readonly property bool hidden:
         Qt.application.state === Qt.ApplicationSuspended ||
@@ -85,8 +84,6 @@ ApplicationWindow {
 
     Utils { id: utils }
 
-    HoverHandler { id: windowHover }
-
     HLoader {
         anchors.fill: parent
         source: py.ready ? "" : "LoadingScreen.qml"