Laravel 8 shift squash & merge (#3029)

* Temporarily moved back config path
* Apply Laravel coding style
* Shift exception handler
* Shift HTTP kernel and middleware
* Shift service providers
* Convert options array to fluent methods
* Shift to class based routes
* Shift console routes
* Ignore temporary framework files
* Shift to class based factories
* Namespace seeders
* Shift PSR-4 autoloading
* Shift config files
* Default config files
* Shift Laravel dependencies
* Shift return type of base TestCase methods
* Shift cleanup
* Applied stylci style changes
* Reverted config files location
* Applied manual changes to Laravel 8 shift

Co-authored-by: Shift <shift@laravelshift.com>

app/Http/Kernel.php

@@ -11,7 +11,7 @@ class Kernel extends HttpKernel
      * These middleware are run during every request to your application.
      */
     protected $middleware = [
-        \BookStack\Http\Middleware\CheckForMaintenanceMode::class,
+        \BookStack\Http\Middleware\PreventRequestsDuringMaintenance::class,
         \Illuminate\Foundation\Http\Middleware\ValidatePostSize::class,
         \BookStack\Http\Middleware\TrimStrings::class,
         \BookStack\Http\Middleware\TrustProxies::class,