Explicitly specify loopback IP when exposing container ports

[ok300]

The common way ports are exposed in docker 8001:8001 is actually equivalent to 0.0.0.0:8001:8001, which binds the port to all of the host's IPs.

Since docker bypasses local firewalls like ufw and iptables (docker/for-linux#690) , a user that would follow try to run these containers on a VPS VM could inadvertently expose each container's mapped ports to the internet.

To follow security best practices, this PR switches to a port notation that explicitly binds it to the host's loopback IP.

Related to pubky/pubky-core#288, pubky/pubky-nexus#676

[SpontaneousOverthrow]

could you check please that stack is working, make sure to test registration workflow using pubky ring
we have couple of local addresses that are used, for example for accessing nexus,httprelay and homeserver, because this services only exposed on localhost they wont be reachable.

[SpontaneousOverthrow]

subj