docs: [#1096] add mod doc the banning mod

src/servers/udp/server/banning.rs

@@ -1,3 +1,13 @@
+//! Banning service for UDP tracker.
+//! 
+//! It bans clients that send invalid connection id's.
+//! 
+//! It uses a Counting Bloom Filter to keep track of the number of connection id 
+//! errors per ip. That means there can be false positives, but not false 
+//! negatives.
+//! 
+//! 1 out of 100000 requests will be a false positive and the client will not
+//! receive a response.
 use std::net::IpAddr;
 
 use bloom::{CountingBloomFilter, ASMS};