Optimize var.get_role

It will now return as soon as it finds the role for the player,
instead of calling var.list_players_and_roles every single time.
I haven't tested in a real-world scenario, but in a test game
with 10000 players (don't ask), the speed improvement is very clear
(~1-2s per player when sending out nighttime PMs instead of ~10s).

src/settings.py

@@ -345,7 +345,12 @@ def list_players_and_roles():
             plr[p] = x
     return plr
 
-get_role = lambda plyr: list_players_and_roles()[plyr]
+def get_role(p):
+    for role, pl in ROLES.items():
+        if role in TEMPLATE_RESTRICTIONS.keys():
+            continue # only get actual roles
+        if p in pl:
+            return role
 
 def get_reveal_role(nick):
     if HIDDEN_TRAITOR and get_role(nick) == "traitor":