[Quest API] Add RemoveAlternateCurrencyValue() to Perl/Lua (#4190)

# Perl
- Add `$client->RemoveAlternateCurrencyValue(currency_id, amount)`.

# Lua
- Add `client:RemoveAlternateCurrencyValue(currency_id, amount)`.

# Notes
- Allows operators to more easily remove alternate currencies, returns a `bool`, `false` if failed`, `true` if succeeded.
- Added `Zone::DoesAlternateCurrencyExist` that will reject setting, removing, or adding  to a currency that does not exist.

zone/zone.cpp

@@ -3318,4 +3318,15 @@ void Zone::SetSecondsBeforeIdle(uint32 seconds_before_idle)
 	Zone::m_seconds_before_idle = seconds_before_idle;
 }
 
+bool Zone::DoesAlternateCurrencyExist(uint32 currency_id)
+{
+	return std::any_of(
+		AlternateCurrencies.begin(),
+		AlternateCurrencies.end(),
+		[&](const auto& c) {
+			return c.id == currency_id;
+		}
+	);
+}
+
 #include "zone_loot.cpp"