Add additional arguments to config:set command

[maormagori]

Currently, any environment variable setting happens separately and causes the container to restart. I think adding the possibility of setting all the variables together, which is already supported by dokku, will help those of us who set the env vars as part of their CI.

This is not a must since most of the users will only add a secret once and won't need to change it again but IMO it's nice to have.