Docker: Application build via Docker for development

[ali-ichk]

Description
This PR reviews and adds some changes to the the Dockerfile introduced by Zaidmasri in #2037, resolving some issues that prevented Gibbon from running correctly in a Docker environment.

Motivation and Context
Currently, setting up a local Gibbon development environment requires manually configuring PHP, Apache, and MySQL, which can be error-prone and inconsistent across operating systems (macOS, Windows, Linux).

This change solves the following problems:

Simplifies Onboarding: New contributors can spin up a fully working instance with a single command.
Dependency Management: Ensures all contributors use the exact same PHP version (8.2) and extensions (bcmath, intl, gd, etc.) required by Gibbon v31+.
Isolation: Keeps the database and application files isolated from the host machine, preventing system clutter.

How Has This Been Tested?
Tested locally on macOS (Apple Silicon) using Docker Desktop 29.2.1 with the following steps:

Built the image: docker compose -f docker-compose.yaml -f docker-compose.dev.yaml up -d --build
Verified all required PHP extensions are present: docker exec gibbon_app php -m
Verified all PHP ini values meet Gibbon's requirements via php -r "echo ini_get(...)"
Verified AllowOverride All is active: docker exec gibbon_app grep AllowOverride /etc/apache2/apache2.conf
Verified Apache config syntax: docker exec gibbon_app apachectl configtest → Syntax OK
Verified Composer dependencies are satisfied: docker exec gibbon_app composer check-platform-reqs
Verified sensitive files ([.htaccess], [composer.json], [phpstan.neon], [gibbon.sql]) return 403
Confirmed Gibbon web installer loads at http://localhost:8888 with all system requirement checks passing
Confirmed database connection succeeds from the installer using the Docker Compose credentials

[pli888]

Hi @ali-ichk

Nice work, I've made some comments to try to speed up image building.

Looking ahead, we should think about how to restore the database with test data and also show how developers can run tests on this Docker-based Gibbon development environment. This can be done in separate PRs though.

[ali-ichk]

Hi @pli888 Thank you for your suggestions. I have made some changes based on your comments. If you have a moment, could you have a quick look and see if this looks okay to be merged to the core? Thank you for your time!!

[pli888]

Looks good to me. Happy to approve.

[SKuipers]

Thanks @ali-ichk and @pli888 for working on this PR, I'm happy to approve and merge.