chore(ci): port CI from drone to GitHub workflows

[phil-davis]

and bump PHP to 8.3, and core to 11.

and apply latest test-php-style-fix suggestions.

[phil-davis]

Note:
The drone script had:

"appInstallCommandPhp": "composer install"

in its config.

That caused a step to be done early after fetching the app that does a composer install

I am not sure why that was needed (and not needed in most other apps)

CI fails in the workflows like:
https://github.com/owncloud/gallery/actions/runs/23581921823/job/68666430073?pr=869

enabling apps
An unhandled exception has been thrown:
Error: Failed opening required '/home/runner/work/gallery/gallery/apps/gallery/appinfo/../vendor/autoload.php' (include_path='/home/runner/work/gallery/gallery/apps:/home/runner/work/gallery/gallery/apps-external') in /home/runner/work/gallery/gallery/apps/gallery/appinfo/application.php:17
Stack trace:
#0 /home/runner/work/gallery/gallery/lib/private/Autoloader.php(132): require_once()
#1 /home/runner/work/gallery/gallery/apps/gallery/appinfo/app.php(19): OC\Autoloader->load()
#2 /home/runner/work/gallery/gallery/lib/private/legacy/app.php(253): require_once('...')
#3 /home/runner/work/gallery/gallery/lib/private/legacy/app.php(192): OC_App::requireAppFile()
#4 /home/runner/work/gallery/gallery/lib/private/legacy/app.php(125): OC_App::loadApp()
#5 /home/runner/work/gallery/gallery/lib/private/Console/Application.php(103): OC_App::loadApps()
#6 /home/runner/work/gallery/gallery/console.php(95): OC\Console\Application->loadCommands()
#7 /home/runner/work/gallery/gallery/occ(11): require_once('...')
#8 {main}

The reusable-workflows probably need some option to specify an optional command to do after cloning the app.