Add ghostrole jobban option

code/__DEFINES/role_preferences.dm

@@ -43,6 +43,7 @@
 #define ROLE_DRONE				"drone"
 #define ROLE_DEATHSQUAD			"deathsquad"
 #define ROLE_EVENTMISC			"eventmisc"
+#define ROLE_GHOST				"ghost role"
 
 //Missing assignment means it's not a gamemode specific role, IT'S NOT A BUG OR ERROR.
 //The gamemode specific ones are just so the gamemodes can query whether a player is old enough

code/__DEFINES/rolebans.dm

@@ -25,6 +25,7 @@ var/global/list/other_roles = list(
 	ROLE_SENTIENT,
 	ROLE_NYMPH,
 	ROLE_ERT,
+	ROLE_GHOST,
 	"AntagHUD",
 	"Records"
 )

code/modules/awaymissions/corpse.dm

@@ -28,7 +28,7 @@
 	var/datum/disease/disease = null //Do they start with a pre-spawned disease?
 	var/mob_color //Change the mob's color
 	var/assignedrole
-	var/banType = "lavaland"
+	var/banType = ROLE_GHOST
 	var/ghost_usable = TRUE