Add option for saged posts to be sent to WHs or not

[kinoko87]

Pull Requests 4 Kokonotsuba

Before creating your pull request, make sure it follows this small checklist so everything can be nice and epic

• [ ] In the case that it is a fix: Highlights what issue the pull request is fixing
  • (Not a fix)
• [x] Summarises what the changes will do
  • Adds a constant in config.php for disabling/enabling sending saged posts to WHs
• [ ] Has been tested, preferably with this parameters
  • Debian 10
  • nginx
  • MariaDB
  • PHP 7.3
  • If you're unable to, just test it on your system, as in most cases it will work on Heyuri too

If your pull request fits these requirements, you're ready to send it off

_{* And if you're adding any significant pieces of code, make sure to document it using comments!}