Set default to InMemory so there is no exception on first run

Author: linkdotnet

src/LinkDotNet.Blog.Web/appsettings.json

@@ -19,7 +19,7 @@
     "BackgroundUrl": "assets/profile-background.webp",
     "ProfilePictureUrl": "assets/profile-picture.webp"
   },
-  "PersistenceProvider": "SqlServer",
+  "PersistenceProvider": "InMemory",
   "ConnectionString": "",
   "DatabaseName": "",
   "Auth0": {