tdf#124237 Qt5 get link colors from theme

... which includes normal and visited link colors.

Change-Id: Id53850c4700f71d007b59289b135d3c031348f2d
Reviewed-on: https://gerrit.libreoffice.org/69591
Tested-by: Jenkins
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>
diff --git a/vcl/qt5/Qt5Frame.cxx b/vcl/qt5/Qt5Frame.cxx
index b4d1a98..65055e8 100644
--- a/vcl/qt5/Qt5Frame.cxx
+++ b/vcl/qt5/Qt5Frame.cxx
@@ -912,6 +912,8 @@
    Color aMid = toColor(pal.color(QPalette::Active, QPalette::Mid));
    Color aHigh = toColor(pal.color(QPalette::Active, QPalette::Highlight));
    Color aHighText = toColor(pal.color(QPalette::Active, QPalette::HighlightedText));
    Color aLink = toColor(pal.color(QPalette::Active, QPalette::Link));
    Color aVisitedLink = toColor(pal.color(QPalette::Active, QPalette::LinkVisited));

    style.SetSkipDisabledInMenus(true);

@@ -956,6 +958,10 @@
    style.SetHighlightColor(aHigh);
    style.SetHighlightTextColor(aHighText);

    // Links
    style.SetLinkColor(aLink);
    style.SetVisitedLinkColor(aVisitedLink);

    // Tooltip
    style.SetHelpColor(toColor(QToolTip::palette().color(QPalette::Active, QPalette::ToolTipBase)));
    style.SetHelpTextColor(