make commands services

[lsmith77]

https://symfony.com/doc/current/console/commands_as_services.html

[stefandoorn]

Added PR (#58). Downside is that the exporter command requires the container at this moment to get the proper repository. Probably would be nice to have a command instance that can have the proper repository injected, but that might be next improvement. Not sure if we can do that just with the services.yml we currently have (maybe via a factory or smth) or that we need to use compiler passes for it.

[lsmith77]

we can use this symfony/symfony#21553

[stefandoorn]

How would that look in practice?

[lsmith77]

we would inject a service locator service, which would be define dynamically with all the exporter services.

[lsmith77]

I created #74 for the switch to service locator