Use long-form command options instead of short-form, for clarity

[rdimaio]

e.g. https://github.com/rucio/documentation/blob/88192103317421e7f9385d837bee2a0df78c00ae/docs/operator/setting_up_demo.md#using-the-environment-including-storage

docker-compose --file etc/docker/dev/docker-compose.yml up -d

Using --detach instead of -d might be clearer as to why we use this flag. (although in this context, I guess it's a lot more common to see up -d instead - but in general we have some shell commands around the docs that might have too many shortened flags, which might be a bit confusing)