move Windows app to Windows folder, create folder for Web, create simplest web api service

Windows/Azaion.Annotator/Extensions/DirectoryInfoExtensions.cs

@@ -0,0 +1,10 @@
+using System.IO;
+
+namespace Azaion.Annotator.Extensions;
+
+public static class DirectoryInfoExtensions
+{
+    public static IEnumerable<FileInfo> GetFiles(this DirectoryInfo dir, params string[] searchExtensions) =>
+        dir.GetFiles("*.*", SearchOption.AllDirectories)
+            .Where(f => searchExtensions.Any(s => f.Name.Contains(s, StringComparison.CurrentCultureIgnoreCase))).ToList();
+}