Orobox documentation

Full reference docs, split out of the README so it can stay a landing page.

• Configuration — .orobox.yaml, installation types, environment files, global flags.
• Customizing the environment — packages, PHP extensions, your own Dockerfile, php_ini, host ports, env variables, extra services through a compose override, ready-made recipes (Varnish, Selenium, SFTP, Blackfire), what reaches the deploy pipeline.
• Commands — create, init, up, down, shell, logs, console, test, clear, run, extend, test-init, db, self-update.
• QA tools — qa-init, qa, the PHPStan baseline, the shared vendor tree, project configuration files, running checks in CI, reports.
• Deployment — deploy-init, ci-init, deploy, keeping development files out of a release, pipeline caching.
• Debugging with Xdebug — enabling/disabling Xdebug, CLI/consumer/cron, PHPStorm setup.
• Domains, SSL and WebSocket
• Internal structure and development — the services Orobox wires up, and the contributor Makefile targets.
• Comparison with alternatives — how Orobox relates to the official Oro Docker docs, community stacks, and generic tools (DDEV, Lando, Warden).