Update Benchmarks test app from Program + Startup to just Program.cs (aspnet#2141)

* Update Benchmarks test app from Program + Startup setup to new Program only setup.
* Add in the application started and application shutting down output (and a few others) so that we can still start testing once we get "Application started" message.

Author: LoopedBard3

src/Benchmarks/Data/World.cs

@@ -10,13 +10,15 @@ namespace Benchmarks.Data
     [Table("world")]
     public class World
     {
+        [UseColumnAttribute]
         [Column("id")]
         public int Id { get; set; }
 
         [IgnoreDataMember]
         [NotMapped, DbValue(Ignore = true)]
         public int _Id { get; set; }
 
+        [UseColumnAttribute]
         [Column("randomnumber")]
         public int RandomNumber { get; set; }
     }