Create a script that gathers debug information from a host running the agent ISO and exports it in a standard format so that we can ask customers to provide it for debugging when something has gone wrong (and also use it in CI).

For now, it is fine to require the user to ssh into the host to run the script. The script should be already in place inside the agent ISO.

The output should probably be a compressed tar file. That file could be saved locally, or potentially piped to stdout so that a user only has to run a command like: ssh node0 -c agent-gather >node0.tgz

Things we need to collect:

• systemctl status and journal for each of the systemd services created by the agent installer (ideally this should be determined programmatically so we can't forget to add any)
• network information: ifconfig; ip -j -p addr
• Data supplied by the agent installer in /etc/assisted/*
• /etc/containers/registries.conf
• /etc/assisted-service/node0 (if it exists)
• /usr/local/share/assisted-service/*.env