GreenField: Store OnChain Payment Method (#2157)

* GreenField: Store set payment methods

* add swagger docs

* fix swagger

BTCPayServer.Client/Models/OnChainPaymentMethodData.cs

@@ -0,0 +1,38 @@
+namespace BTCPayServer.Client.Models
+{
+    public class OnChainPaymentMethodData
+    {
+        /// <summary>
+        /// Whether the payment method is enabled
+        /// </summary>
+        public bool Enabled { get; set; }
+
+        /// <summary>
+        /// Whether the payment method is the default
+        /// </summary>
+        public bool Default { get; set; }
+
+        /// <summary>
+        /// Crypto code of the payment method
+        /// </summary>
+        public string CryptoCode { get; set; }
+
+        /// <summary>
+        /// The derivation scheme
+        /// </summary>
+        public string DerivationScheme { get; set; }
+
+        public OnChainPaymentMethodData()
+        {
+        }
+
+        public OnChainPaymentMethodData(string cryptoCode, string derivationScheme, bool enabled,
+            bool defaultMethod)
+        {
+            Enabled = enabled;
+            Default = defaultMethod;
+            CryptoCode = cryptoCode;
+            DerivationScheme = derivationScheme;
+        }
+    }
+}