UX Overhaul Part 1 (#3047)

Co-authored-by: Joseph Milazzo <joseph.v.milazzo@gmail.com>

API/Entities/Interfaces/IHasCoverImage.cs

@@ -0,0 +1,19 @@
+namespace API.Entities.Interfaces;
+
+public interface IHasCoverImage
+{
+    /// <summary>
+    /// Absolute path to the (managed) image file
+    /// </summary>
+    /// <remarks>The file is managed internally to Kavita's APPDIR</remarks>
+    public string? CoverImage { get; set; }
+
+    /// <summary>
+    /// Primary color derived from the Cover Image
+    /// </summary>
+    public string? PrimaryColor { get; set; }
+    /// <summary>
+    /// Secondary color derived from the Cover Image
+    /// </summary>
+    public string? SecondaryColor { get; set; }
+}