feat!: support only .NET Framework 4.7.2

In order to conform with the plugin format and the workflow, the .csproj
file was moved up a level to the root of the `src` folder and the
solution file was renamed.

Workflows were also changed to match the plugin workflows.

BREAKING CHANGE: Supports ONLY .NET Framework 4.7.2

src/XSigUtility/Tokens/XSigAnalogToken.cs

@@ -0,0 +1,88 @@
+using System;
+
+namespace PepperDash.Core.Intersystem.Tokens
+{
+    /// <summary>
+    /// Represents an XSigAnalogToken
+    /// </summary>
+    public sealed class XSigAnalogToken : XSigToken, IFormattable
+    {
+        private readonly ushort _value;
+
+        /// <summary>
+        /// Constructor
+        /// </summary>
+        /// <param name="index"></param>
+        /// <param name="value"></param>
+        public XSigAnalogToken(int index, ushort value)
+            : base(index)
+        {
+            // 10-bits available for analog encoded data
+            if (index >= 1024 || index < 0)
+                throw new ArgumentOutOfRangeException("index");
+
+            _value = value;
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        public ushort Value
+        {
+            get { return _value; }
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        public override XSigTokenType TokenType
+        {
+            get { return XSigTokenType.Analog; }
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <returns></returns>
+        public override byte[] GetBytes()
+        {
+            return new[] {
+                (byte)(0xC0 | ((Value & 0xC000) >> 10) | (Index - 1 >> 7)),
+                (byte)((Index - 1) & 0x7F),
+                (byte)((Value & 0x3F80) >> 7),
+                (byte)(Value & 0x7F)
+            };
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="offset"></param>
+        /// <returns></returns>
+        public override XSigToken GetTokenWithOffset(int offset)
+        {
+            if (offset == 0) return this;
+            return new XSigAnalogToken(Index + offset, Value);
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <returns></returns>
+        public override string ToString()
+        {
+            return Index + " = 0x" + Value.ToString("X4");
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="format"></param>
+        /// <param name="formatProvider"></param>
+        /// <returns></returns>
+        public string ToString(string format, IFormatProvider formatProvider)
+        {
+            return Value.ToString(format, formatProvider);
+        }
+    }
+}