[ADD] New entities for library db

Manager.Data/Models/LibraryContext/ChannelEntity.cs

@@ -0,0 +1,15 @@
+namespace Manager.Data.Models.LibraryContext;
+
+public class ChannelEntity
+{
+    public required string Id { get; set; }
+    public string? Name { get; set; }
+    public string? Description { get; set; }
+    public DateTime JoinedDate { get; set; }
+    public long Subscribers { get; set; }
+    public long TotalVideos { get; set; }
+    public long TotalViews { get; set; }
+    
+    public DateTime AddedDate { get; set; }
+    public DateTime ModifiedDate { get; set; }
+}