Add config options to enable stats in container

[cyqsimon]

This adds a way to enable stats in containers.

[cyqsimon]

Also something worth considering: adding environment variable configuration support within clap, so that we would no longer need the bespoke scripting in docker-entrypoint.sh. For an example, see svenstaro/miniserve#1160.

This would also allow other deployment methods to use environment variable configuration too, for example when using systemd.

[niklasf]

Thanks!