net-mgmt/librenms: Update to 24.4.0

re: https://github.com/librenms/librenms/releases/tag/24.4.0

While here, add a missing dep: sysutils/py-psutil

Also, note that the service is not starting up properly for me in a
jail. This may also affect non-jail hosts; I don't know. This is not
new to this release. Monitor /var/log/librenms/*.log and if you see
'Unable to launch a new process', then restart the service via:

service librenms restart

After that, all is well.