Removed submodule Extern/NFD-Extended

Author: Atraxus

.gitmodules

@@ -27,4 +27,4 @@
 	url = https://github.com/alpaka-group/alpaka.git
 [submodule "Extern/portable-file-dialogs"]
 	path = Extern/portable-file-dialogs
-	url = https://github.com/samhocevar/portable-file-dialogs.git
+	url = https://github.com/samhocevar/portable-file-dialogs.git