Restructure solution a bit

src/Spectre.Console/Padding.cs

@@ -0,0 +1,86 @@
+using System;
+
+namespace Spectre.Console
+{
+    /// <summary>
+    /// Represents a measurement.
+    /// </summary>
+    public struct Padding : IEquatable<Padding>
+    {
+        /// <summary>
+        /// Gets the left padding.
+        /// </summary>
+        public int Left { get; }
+
+        /// <summary>
+        /// Gets the right padding.
+        /// </summary>
+        public int Right { get; }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Padding"/> struct.
+        /// </summary>
+        /// <param name="left">The left padding.</param>
+        /// <param name="right">The right padding.</param>
+        public Padding(int left, int right)
+        {
+            Left = left;
+            Right = right;
+        }
+
+        /// <inheritdoc/>
+        public override bool Equals(object? obj)
+        {
+            return obj is Padding padding && Equals(padding);
+        }
+
+        /// <inheritdoc/>
+        public override int GetHashCode()
+        {
+            unchecked
+            {
+                var hash = (int)2166136261;
+                hash = (hash * 16777619) ^ Left.GetHashCode();
+                hash = (hash * 16777619) ^ Right.GetHashCode();
+                return hash;
+            }
+        }
+
+        /// <inheritdoc/>
+        public bool Equals(Padding other)
+        {
+            return Left == other.Left && Right == other.Right;
+        }
+
+        /// <summary>
+        /// Checks if two <see cref="Padding"/> instances are equal.
+        /// </summary>
+        /// <param name="left">The first <see cref="Padding"/> instance to compare.</param>
+        /// <param name="right">The second <see cref="Padding"/> instance to compare.</param>
+        /// <returns><c>true</c> if the two instances are equal, otherwise <c>false</c>.</returns>
+        public static bool operator ==(Padding left, Padding right)
+        {
+            return left.Equals(right);
+        }
+
+        /// <summary>
+        /// Checks if two <see cref="Padding"/> instances are not equal.
+        /// </summary>
+        /// <param name="left">The first <see cref="Padding"/> instance to compare.</param>
+        /// <param name="right">The second <see cref="Padding"/> instance to compare.</param>
+        /// <returns><c>true</c> if the two instances are not equal, otherwise <c>false</c>.</returns>
+        public static bool operator !=(Padding left, Padding right)
+        {
+            return !(left == right);
+        }
+
+        /// <summary>
+        /// Gets the horizontal padding.
+        /// </summary>
+        /// <returns>The horizontal padding.</returns>
+        public int GetHorizontalPadding()
+        {
+            return Left + Right;
+        }
+    }
+}