[5.6] Remove monologConfigurator infrastructure completely

[mfn]

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 but is gone now (the removal happened in #22635 ).

Note

Applying this PR is a "hard break".

So far in 5.6 it's a "soft break", as in: even if you have used configureMonologUsing, it's not called anymore but you wouldn't notice until later. After merging this, anyone using it would immediately see a hard break in the application.

As I assume it's not coming back anymore, I additionally suggest to note this in the upgrade guide as a breaking change to 5.5

[manoj-manoharan-backup-old]

I need to configure S3 client adapter to logs, I'm currently using 5.5 and the configuration is working perfectly. Now how do i manually configure the logs to be written in S3 in 5.6.

`$app->configureMonologUsing(function ($monolog) use ($app) {

    $s3FileKey = \App\Helper\Util::getS3LogPath();

    $adapter = \Illuminate\Support\Facades\Storage::disk('s3')->getAdapter();
    $client = $adapter->getClient();
    $client->registerStreamWrapper();

    $s3Stream = "s3://{$adapter->getBucket()}/{$s3FileKey}";
    $streamHandler = (new \Monolog\Handler\StreamHandler($s3Stream));

    $monolog->pushHandler($streamHandler);
});`

Now how do i migrate this code to 5.6