Greentext antag datum and OnRoundend hook. (#35584)

* Greentext antag datum and OnRoundend hook.

* review stuff

code/modules/antagonists/greentext/greentext.dm

@@ -0,0 +1,19 @@
+/datum/antagonist/greentext
+	name = "winner"
+	show_in_antagpanel = FALSE
+	show_name_in_check_antagonists = TRUE //Not that it will be there for long
+
+/datum/antagonist/greentext/proc/forge_objectives()
+	var/datum/objective/O = new /datum/objective("Succeed")
+	O.completed = TRUE //YES!
+	O.owner = owner
+	objectives += O
+	owner.objectives += objectives
+
+/datum/antagonist/greentext/on_gain()
+	forge_objectives()
+	. = ..()
+
+/datum/antagonist/greentext/on_removal()
+	owner.objectives -= objectives
+	. = ..()