Adds Automuting

Adds a system adapted from Aurora that will automatically mute someone if they say things too quickly in IC, OOC, Deadchat, Ahelp, or Pray.

code/modules/client/spam_prevention.dm

@@ -0,0 +1,13 @@
+// Based on Aurora's anti-spam system.
+/client/
+	var/last_message_time = 0
+	var/spam_alert = 0
+
+/client/proc/handle_spam_prevention(var/mute_type = MUTE_ALL, var/spam_delay = 1 SECOND)
+	if(world.time - last_message_time < spam_delay)
+		spam_alert++
+		if(spam_alert > 3)
+			cmd_admin_mute(src.mob, mute_type, 1)
+	else
+		spam_alert = max(0, spam_alert--)
+	last_message_time = world.time