Drop symfony/console dependency

[sanderdlm]

Having the symony/console dependency can be problematic when trying to use this tool as a Composer dependency rather than a PHAR. Since there is only 1 command, and a very simple one at that, we could replace the SingleCommandApplication with a very basic vanilla implementation (see https://dev.to/erikaheidi/bootstrapping-a-cli-php-application-in-vanilla-php-4ee).