Add config option to disable same-CID popup "YOU'LL BE BANNED STOP IT"

This is seriously fucking annoying when testing local changes. Only a
config option instead of being removed completely because I am actually
going to go fucking insane without this being gone.

code/controllers/configuration.dm

@@ -173,6 +173,7 @@
 	var/dsay_allowed = 1
 
 	var/disable_lobby_music = 0 // Disables the lobby music
+	var/disable_cid_warn_popup = 0 //disables the annoying "You have already logged in this round, disconnect or be banned" popup, because it annoys the shit out of me when testing.
 
 /datum/configuration/New()
 	var/list/L = subtypesof(/datum/game_mode)
@@ -549,6 +550,9 @@
 				if("disable_lobby_music")
 					config.disable_lobby_music = 1
 
+				if("disable_cid_warn_popup")
+					config.disable_cid_warn_popup = 1
+
 				else
 					diary << "Unknown setting in configuration: '[name]'"