Add tutrorial on configuring XDebug

[samdark]

With and without using Docker for:

1. Web.
2. Command line.
3. Tests.

IDEs to cover:

1. PhpStorm
2. VSCode

Important things to mention for PhpStorm:

1. Settings → PHP → Servers correct path mappings. Root of the project in container should match root in the local file system.
2. Installing browser extension from PHP → Debug.
3. SERVER_NAME=localhost SERVER_PORT=80 XDEBUG_CONFIG="idekey=phpstorm client_host=host.docker.internal"

Docker compose on Linux extra config:

extra_hosts:
  - "host.docker.internal:host-gateway"