Introduce administration sub-command

[blt]

Per conversation with @doubleyou, it would be very useful to have an administration sub-command to let operators quickly see what the status of cernan is. Useful information:

• what are the ship-statuses of the sinks
• what is the position of the mspc reader / how quickly is it churning through

This implies some notion of self-telemetry which dovetails with #88 and #117.