enable "StopForumSpam" to filter ill-intentioned registration

# description

In nodebb, it requests to api.StopForumSpam.org to filter spams for signup. But it is not available in China. To enable it, may apply other plugin or other vendor's api.
# solution

1) get other plugin
Try another way to implement it. (Refer to https://www.stopforumspam.com/country/cn)

2) use other vendor's api in China
# todo, investigate or search options.
