[ENHANCEMENT] Cooled camera - No warmup functionality

[pgriffin17]

Is your feature request related to a problem? Please describe.
A safe cooled-camera warmup procedure is needed in Observatory.disconnect_all() and Observatory.shutdown() to prevent sensor defects.

Describe the solution you'd like
If the cooler is on when shutdown/disconnect_all is called, either throw a warning, or, more beneficially, the camera setpoint should be slowly increased to ambient temperature over several minutes.

Additional context
This is standard practice to prevent glass/sensors from cracking due to rapid warmup.