feat: Remove docker container after running "composer install"

[bfanger]

• Remove docker container after "composer install" was completed
• Removed incorrect indent_size (2 spaces was used) setting
• Fixed warning: "the attribute version is obsolete, it will be ignored, please remove it to avoid potential confusion"
• Use "docker compose" instead of the deprecated "docker-compose" command
• Use Mailpit instead of Mailhog