Service Transactions and Service Provider

added BillPayment and ServiceProvider resources (#58)

* added billy_payments and service_providers

* changed service_provider fields and query type for bill_payments

* added tests for new resources and fixed BillPayment model

* added categories to ServiceProvider

* removed ServiceProvider resource, not going in that direction yet

* readded ServiceProvider as a resource

* added tests for ServiceProvider resource

* bump version

* testing pr workflow