Add -all flag on system and group cards (#216)

* Show group count on stats card

* Add -all flag on system and group cards
Shows full count, including private members.

* fix stuff broken by merging conflicts

PluralKit.Bot/Commands/Privacy/ContextPrivacyExt.cs

@@ -44,5 +44,14 @@ namespace PluralKit.Bot
             ctx.PopArgument();
             return subject;
         }
+
+        public static bool MatchPrivateFlag(this Context ctx, LookupContext pctx)
+        {
+            var privacy = true;
+            if (ctx.MatchFlag("a", "all")) privacy = false;
+            if (pctx == LookupContext.ByNonOwner && !privacy) throw Errors.LookupNotAllowed;
+
+            return privacy; 
+        }
     }
 }