Add Env Var to disable second level cache

This is an attempt to track down possible causes of remaining database lockups. Add an environment variable to disable the second-level cache entirely to see if it works better on systems that still experience lockups.

Signed-off-by: gnattu <gnattuoc@me.com>

Jellyfin.Server/Extensions/WebHostBuilderExtensions.cs

@@ -85,6 +85,6 @@ public static class WebHostBuilderExtensions
                     logger.LogInformation("Kestrel listening to unix socket {SocketPath}", socketPath);
                 }
             })
-            .UseStartup(_ => new Startup(appHost));
+            .UseStartup(_ => new Startup(appHost, startupConfig));
     }
 }