feat: move PD Core into Essentials

src/PepperDash.Core/XSigUtility/Serialization/IXSigSerialization.cs

@@ -0,0 +1,25 @@
+using System.Collections.Generic;
+using PepperDash.Core.Intersystem.Tokens;
+
+namespace PepperDash.Core.Intersystem.Serialization
+{
+    /// <summary>
+    /// Interface to determine XSig serialization for an object.
+    /// </summary>
+    public interface IXSigSerialization
+    {
+        /// <summary>
+        /// Serialize the sig data
+        /// </summary>
+        /// <returns></returns>
+        IEnumerable<XSigToken> Serialize();
+
+        /// <summary>
+        /// Deserialize the sig data
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="tokens"></param>
+        /// <returns></returns>
+        T Deserialize<T>(IEnumerable<XSigToken> tokens) where T : class, IXSigSerialization;
+    }
+}