Added login user count colorization (#3651)

Credits to @4144 for his implementation of the feature.

conf/login_athena.conf

@@ -110,6 +110,16 @@ start_limited_time: -1
 // NOTE: Will not work with clients that use <passwordencrypt>
 use_MD5_passwords: no
 
+// User count colorization on login window (requires PACKETVER >= 20170726)
+// Disable colorization and description in general?
+usercount_disable: no
+// Amount of users that will display in green
+usercount_low: 200
+// Amount of users that will display in yellow
+usercount_medium: 500
+// Amount of users that will display in red
+usercount_high: 1000
+
 // Ipban features
 ipban_enable: yes
 // Dynamic password failure ipban system