Restructure solution a bit

src/Spectre.Console/Widgets/GridColumn.cs

@@ -0,0 +1,54 @@
+namespace Spectre.Console
+{
+    /// <summary>
+    /// Represents a grid column.
+    /// </summary>
+    public sealed class GridColumn : IColumn
+    {
+        private Padding _padding;
+
+        /// <summary>
+        /// Gets or sets the width of the column.
+        /// If <c>null</c>, the column will adapt to it's contents.
+        /// </summary>
+        public int? Width { get; set; }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether wrapping of
+        /// text within the column should be prevented.
+        /// </summary>
+        public bool NoWrap { get; set; }
+
+        /// <summary>
+        /// Gets or sets the padding of the column.
+        /// </summary>
+        public Padding Padding
+        {
+            get => _padding;
+            set
+            {
+                HasExplicitPadding = true;
+                _padding = value;
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets the alignment of the column.
+        /// </summary>
+        public Justify? Alignment { get; set; }
+
+        /// <summary>
+        /// Gets a value indicating whether the user
+        /// has set an explicit padding for this column.
+        /// </summary>
+        internal bool HasExplicitPadding { get; private set; }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="GridColumn"/> class.
+        /// </summary>
+        public GridColumn()
+        {
+            _padding = new Padding(0, 2);
+        }
+    }
+}