Utilities: Use Vector<String> positional arguments in some places

There are more places we can use these, I just picked some that felt
like they improved the code.

Userland/Utilities/tar.cpp

@@ -175,7 +175,7 @@ int main(int argc, char** argv)
             }
         };
 
-        for (const String path : paths) {
+        for (auto const& path : paths) {
             if (Core::File::is_directory(path)) {
                 add_directory(path, add_directory);
             } else {