qt5.12: Add patches for QTBUG-73459 and QTBUG-69077

QT 5.12 introduced a regression, where a QT program wouldn't show its
tray icon, if there was no tray bar during program startup. (QTBUG-73459)

QT 5.12 introduced a regression, where qtwebengine applications would
freeze in some wayland compositors if a surface from the instance was not
visible (for example having a qutebrowser window on another workspace in
sway would freeze all qutebrowser windows).

Both got fixed already in Qt 5.12.4, but according to #57042 and its
sibling issues/PRs it doesn't seem to get fixed in near future for
nixpkgs.

pkgs/development/libraries/qt-5/5.12/default.nix

@@ -53,6 +53,7 @@ let
     qtbase = [
       ./qtbase.patch
       ./qtbase-fixguicmake.patch
+      ./qtbase-trayicons.patch # can be removed with 5.12.4 or 5.13
     ];
     qtdeclarative = [ ./qtdeclarative.patch ];
     qtscript = [ ./qtscript.patch ];
@@ -67,6 +68,10 @@ let
         ./qtwebkit-darwin-no-qos-classes.patch
       ];
     qttools = [ ./qttools.patch ];
+    qtwayland = [
+      ./qtwayland-fix-webengine-freezeups-1.patch # can be removed with 5.12.4 or 5.13
+      ./qtwayland-fix-webengine-freezeups-2.patch # can be removed with 5.12.4 or 5.13
+    ];
   };
 
   qtModule =