Backport PR #421 and #534 to 1.x branch

[lancechentw]

This PR backports hasPackage() from #421 and pagesDirectory() from #534 to 1.x branch. These methods are used in third-party guidelines like inertia-laravel 2.x, and would cause boost:install command to abort with ViewException like below when having combination like Laravel 10 + boost v1 + inertia-laravel v2.

   Illuminate\View\ViewException 

  Call to undefined method Laravel\Boost\Install\Assists\Inertia::pagesDirectory() (View: laravel-repo/storage/framework/views/93dd1b762f2927fece5039c9b2cac4fe.blade.php)

[lancechentw]

Issues #612 and #615 had the same problem, but they were not tied to boost v1 and were resolved by upgrading to boost v2.

[pushpak1300]

Thanks.