Add auto-registration mechanism

- Add User registration mechanism when adding auth provider id to claims, if no User Id corresponds to the auth provider Id
- Swallow unique constraint violation for unique auth provider id on user table, in case of duplicate requests
- Add Serilog logging
- Add no bookmarks and no tags message when none is found on Bookmark List page

YABA.API/Controllers/MiscController.cs

@@ -2,6 +2,7 @@
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
 using System.Net;
+using YABA.API.Settings;
 using YABA.API.ViewModels;
 using YABA.Service.Interfaces;
 
@@ -24,7 +25,7 @@ namespace YABA.API.Controllers
         }
 
         [HttpGet]
-        [Obsolete]
+        [DevOnly]
         [Route("GetWebsiteMetaData")]
         [ProducesResponseType(typeof(GetWebsiteMetaDataResponse), (int)HttpStatusCode.OK)]
         [ProducesResponseType((int)HttpStatusCode.BadRequest)]