Added Hangfire and Hangfire SQLite extension for future task framework. Added a basic directory scanning implementation.

API/Interfaces/IDirectoryService.cs

@@ -1,10 +1,14 @@
 using System.Collections.Generic;
 using System.Threading.Tasks;
+using API.DTOs;
+using API.Entities;
 
 namespace API.Interfaces
 {
     public interface IDirectoryService
     {
         IEnumerable<string> ListDirectory(string rootPath);
+
+        void ScanLibrary(LibraryDto library);
     }
 }