Follows-up: {T158837}
`osmium` is no longer used by the Performance Team. We're currently working on refreshing our hardware. Part of that is consolidating and moving around most of our services. While our plans do include moving some services to a new host, it probably isn't worth reclaiming this server given its age. (Also, our current draft plan is aiming to use VMs, so we wouldn't need osmium anyway.)
------
### Checklist
[x] - all system services confirmed offline from production use
[x] - set all icinga checks to maint mode/disabled while reclaim/decommmission takes place.
[x] - remove system from all lvs/pybal active configuration
[x] - any service group puppet/heira/dsh config removed
[x] - remove site.pp (replace with role(spare::system) if system isn't shut down immediately during this process.)
START NON-INTERRUPPTABLE STEPS
[x] - disable puppet on host
[x] - power down host
[x] - disable switch port
[x] - switch port assignment noted on this task (for later removal) asw-c-eqiad:ge-4/0/20
[x] - remove all remaining puppet references (include role::spare) https://gerrit.wikimedia.org/r/#/c/390028/
[x] - remove production dns entries https://gerrit.wikimedia.org/r/#/c/390029/
[x] - puppet node clean, puppet node deactivate
END NON-INTERRUPPTABLE STEPS
[] - system disks wiped (by onsite)
[] - system unracked and decommissioned (by onsite), update racktables with result
[] - switch port configration removed from switch once system is unracked.
[] - mgmt dns entries removed.