Improved HTTP client (#4740)

* Improved HTTP client

* Change config compat to use auto, rename blacklist

* Fix wrong doc references

src/main.rs

@@ -47,6 +47,7 @@ mod config;
 mod crypto;
 #[macro_use]
 mod db;
+mod http_client;
 mod mail;
 mod ratelimit;
 mod util;