We were super inconsistent about this, with most "new" classes living in
the Ladybird namespace, while "old" ones were in the global namespace,
or even sitting in the Browser namespace.
This prevents memory leaks detected by both Valgrind and ASAN/LSAN.
Valgrind is still suspicious of the leaked JS::VM from
Web::Bindings::main_thread_vm() but there's other issues with leak
checking all the GC'd objects.
Co-Authored-By: Diego Iastrubni <diegoiast@gmail.com>
