allow the site url to be configurable

[IoIxD]

I have made sure all the things still work:

• [x] The index page and privacy policy page is still served
• [x] The sitemap isn't broken.
• [x] The guild listing ((example))[http://localhost:8084/592399417676529688] is still functioning
• [x] A guild's message listing ((example))[http://localhost:8084/592399417676529688/1015021717900513363] is still functioning.
• The following post pages are still functioning:
  • [x] Why the Slash Commands? Why aren't my images working? (very complete page that showcases most of the features)
  • [ ] Post your oshi!.. THE FORUM (the largest page that we serve at over 4,448 messages)
  • [x] Any but not all of the posts in the test forum

[IoIxD]

reviewed on another site