[Backend] Upgrade to Laravel 10.x

[galadhremmin]

Current supported version is Laravel 8.x.

[galadhremmin]

In the latest master branch, I've successfully updated to Laravel 9. But now, I might as well just go all the way to Laravel 10. Updating required shifting servers as Laravel 9+ requires PHP 8.1+. I'm keeping this open until I've upgraded to Laravel 10.