Move app providers after illuminate providers, thus avoid error when registering/booting process is depending on illuminate register/boot is being executed too late.

Solve issues such as laravel/framework#5576

In 5576, `AppServiceProvider::boot()` executed first before `Illuminate\Database\DatabaseServiceProvider::boot()` which would set the connection resolver for Eloquent.

Signed-off-by: crynobone <crynobone@gmail.com>