feat(extensions): created extensions project.

- Moved encoding extensions from application to extensions project to increase the abstraction

EnvelopeGenerator.Web/Controllers/HomeController.cs

@@ -7,7 +7,7 @@ using Microsoft.AspNetCore.Mvc;
 using System.Security.Claims;
 using Microsoft.AspNetCore.Authorization;
 using DigitalData.Core.API;
-using EnvelopeGenerator.Application;
+using EnvelopeGenerator.Extensions;
 using Microsoft.Extensions.Localization;
 using DigitalData.Core.DTO;
 using Microsoft.AspNetCore.Localization;