Remove monologConfigurator infrastructure (#23078)

This was made obsolete with the overhaul of the new logger in 5.6
and isn't applied anymore (i.e. dead code).

It was used in `\Illuminate\Log\LogServiceProvider`

src/Illuminate/Foundation/Application.php

@@ -94,13 +94,6 @@ class Application extends Container implements ApplicationContract, HttpKernelIn
      */
     protected $deferredServices = [];
 
-    /**
-     * A custom callback used to configure Monolog.
-     *
-     * @var callable|null
-     */
-    protected $monologConfigurator;
-
     /**
      * The custom database path defined by the developer.
      *
@@ -1044,39 +1037,6 @@ public function provideFacades($namespace)
         AliasLoader::setFacadeNamespace($namespace);
     }
 
-    /**
-     * Define a callback to be used to configure Monolog.
-     *
-     * @param  callable  $callback
-     * @return $this
-     */
-    public function configureMonologUsing(callable $callback)
-    {
-        $this->monologConfigurator = $callback;
-
-        return $this;
-    }
-
-    /**
-     * Determine if the application has a custom Monolog configurator.
-     *
-     * @return bool
-     */
-    public function hasMonologConfigurator()
-    {
-        return ! is_null($this->monologConfigurator);
-    }
-
-    /**
-     * Get the custom Monolog configurator for the application.
-     *
-     * @return callable
-     */
-    public function getMonologConfigurator()
-    {
-        return $this->monologConfigurator;
-    }
-
     /**
      * Get the current application locale.
      *