Restructured the project structure back to the way it was, there's no reasonable way to split the modules

src/NadekoBot/Db/Models/DbEntity.cs

@@ -0,0 +1,12 @@
+#nullable disable
+using System.ComponentModel.DataAnnotations;
+
+namespace Nadeko.Bot.Db.Models;
+
+public class DbEntity
+{
+    [Key]
+    public int Id { get; set; }
+
+    public DateTime? DateAdded { get; set; } = DateTime.UtcNow;
+}