use qt6 cantata fork

package pulled from nixpkgs issue

modules/overlay-pkgs/cantata/dont-check-for-perl-in-PATH.diff

@@ -0,0 +1,16 @@
+diff --git a/playlists/dynamicplaylists.cpp b/playlists/dynamicplaylists.cpp
+index b85e93b5..3c29f775 100644
+--- a/playlists/dynamicplaylists.cpp
++++ b/playlists/dynamicplaylists.cpp
+@@ -205,11 +205,6 @@ void DynamicPlaylists::start(const QString& name)
+ 		return;
+ 	}
+ 
+-	if (Utils::findExe("perl").isEmpty()) {
+-		emit error(tr("You need to install \"perl\" on your system in order for Cantata's dynamic mode to function."));
+-		return;
+-	}
+-
+ 	QString fName(Utils::dataDir(rulesDir, false) + name + constExtension);
+ 
+ 	if (!QFile::exists(fName)) {