- Fix GetRevenueAnalytics return type by dereferencing metrics struct
- Fix getCarrierMetrics to use int64 for Count and convert to int for ActiveCarriers
- Rename ExchangeRateProvider to RateProviderType for consistency
- Change RatePlanCurrencyIntegrator.exchangeService from pointer to interface type
- Add function documentation comments for NewRatePlanCurrencyIntegrator, SubscribeToPlanWith