Allow to inject the role environment variables into the traefik container as well

[Novtopro]

Could we inject environment variables into the traefik container just like https://github.com/mrsked/mrsk/blob/main/lib/mrsk/commands/app.rb#LL17C17-L17C17 as well? This is useful when we what to use the DNS-01 challenge to generate and renew ACME certificates by provisioning a DNS record and in this case we need to inject some credentials for the provider. For example, if I use godaddy as the provider, I need to provideGODADDY_API_KEY and GODADDY_API_SECRET