Lots of changes to get code ready to add library.

API/Services/DirectoryService.cs

@@ -0,0 +1,21 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Threading.Tasks;
+using API.Interfaces;
+
+namespace API.Services
+{
+    public class DirectoryService : IDirectoryService
+    {
+        public IEnumerable<string> ListDirectory(string rootPath)
+        {
+            // TODO: Filter out Hidden and System folders
+            // DirectoryInfo di = new DirectoryInfo(@path);
+            // var dirs = di.GetDirectories()
+            //     .Where(dir => (dir.Attributes & FileAttributes.Hidden & FileAttributes.System) == 0).ToImmutableList();
+            //
+
+            return Directory.GetDirectories(@rootPath);
+        }
+    }
+}