chore: add hrynco common library solution

- add the standalone HrynCo.Common solution and projects
- include the shared common library source and tests
- add package metadata and a repo gitignore

HrynCo.Common/Tree/BreadcrumbNode.cs

@@ -0,0 +1,19 @@
+namespace HrynCo.Common.Tree;
+
+public sealed record BreadcrumbNode<TKey>
+{
+    public BreadcrumbNode(TKey Id, string Name)
+    {
+        this.Id = Id;
+        this.Name = Name;
+    }
+
+    public TKey Id { get; init; }
+    public string Name { get; init; }
+
+    public void Deconstruct(out TKey Id, out string Name)
+    {
+        Id = this.Id;
+        Name = this.Name;
+    }
+}