Added Payment API's to the HTTP API Base

[duhowise]

Added implementations for the version one of the hubtel payments api into the existing http sdk to streamline development of applications that use the HTTP API SDK. classes added:PaymentsApi functions: RequestPayment(receive money), MakePayment(send money),CheckPaymentStatus(transaction status), OnlineCheckoutV1 and OnlineCheckoutStatusV1

example usage: ` var clientId = ConfigurationManager.AppSettings["ClientId"]; var clientSecret = ConfigurationManager.AppSettings["ClientSecret"]; var merchant = ConfigurationManager.AppSettings["MerchantNumber"]; var host = new ApiHost(new BasicAuth(clientId, clientSecret));

            //Messaging Example
            var messageApi = new MessagingApi(host);
            MessageResponse msg = messageApi.SendQuickMessage("DevUniverse", "+233241952532", "Welcome to planet Hubtel!", true);
            Console.WriteLine(msg.Status);

            //Payment request example
            var payments = new PaymentsApi(host);
            var paymentResponse =
                payments.RequestPayment("233241952532", 0.1M, "Duho wise", "mtn-gh", "Hire Purchase", "http://requestb.in/1minotz1", "http://requestb.in/1minotz1");
            Console.WriteLine(paymentResponse.Data.Description);

            //Payment request example using receive payment class
            var payments = new PaymentsApi(host);
            var paymentResponse =
                payments.RequestPayment(new RecievePayment
                {
                    Amount = 0.1M,
                    Channel = "mtn-gh",
                    ClientReference = "",
                    CustomerEmail = "",
                    CustomerMsisdn = "233241952532",
                    Description = "Hire Purchase",
                    CustomerName = "Duho Wise",
                    PrimaryCallbackUrl = "http://requestb.in/1minotz1",
                    SecondaryCallbackUrl = ""
                });
            Console.WriteLine(paymentResponse.Data.Description);

          //  Transaction Status Check
           var payments = new PaymentsApi(host);
            var statusResponse =
                payments.CheckPaymentStatus(new Transaction
                {
                    HubtelTransactionId = "76dc69dea253404f9924c70a56e589c3"
                });
            Console.WriteLine(statusResponse?.Data?.FirstOrDefault()?.TransactionStatus);

            //Online Checkout status

            var payments = new PaymentsApi(host);
            var statusResponse =
                payments.OnlineCheckoutStatusV1("755b8f0979f34d44");
            Console.WriteLine(statusResponse);

// Online Checkout

            var payments = new PaymentsApi(host);
            var statusResponse =
                payments.OnlineCheckoutV1(new CreatedInvoice
                {
                    Invoice = new Payments.Invoice
                    {
                       Description = "Insurance purchase",
                        TotalAmount = 0.01
                    },
                    Actions = new Actions
                    {
                        CancelUrl = "",
                        ReturnUrl = ""
                    },
                    Store = new Store
                    {
                        LogoUrl = "",
                        Name = "Store Ghana",
                        Phone = "0255899654",
                        PostalAddress = "SOme Address",
                        Tagline = "We make things happen",
                        WebsiteUrl = "",
                    },
                    CustomData = new object()

                });
            Console.WriteLine(statusResponse);`