Working on users view, added infrastructure lib

UserService.Infrastructure/DataModels/Node.cs

@@ -0,0 +1,24 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+
+namespace UserService.Infrastructure.DataModels
+{
+    public abstract class Node : ICloneable
+    {
+        public int Id { get; set; }
+        [Required] public string CommonName { get; set; } = null!;
+        public string? Description { get; set; }
+        public ICollection<Node> Children { get; set; } = new List<Node>();
+        public Node? Parent { get; set; } //Parent
+        public int? ParentId { get; set; }
+
+        public override string ToString() => CommonName;
+
+        public int Level => Parent?.Level + 1 ?? 0;
+
+        /// <inheritdoc />
+        public virtual object Clone() => MemberwiseClone();
+    }
+}