* Prior to this change, the artifact server always binds to the detected
"outbound IP", breaks functionality when that IP is unroutable.
For example, Zscaler assigns the host a local CGNAT address,
100.64.0.1, which is unreachable from Docker Desktop.
* Add the `--artifact-server-addr` flag to allow override of the address
to which the artifact server binds, defaulting to the existing
behaviour.
Fixes: #1559