Enhancement: safe shutdown

[Shnitzelil]

My current architecture is
Two Selenograph services behind hardware load balacner (checking the /ping API status code)

When I wish to restart one of the machines I would like to stop it gently...
my suggestion is to change the return status code from the /ping API to be 5xx or 4xx
Or to change the return value from ok to something else (like "shunting down" or whatever).
Once no new connection will arrive it will be fully shutdown.

Or any suggestion you have...

WDYT?

Issue from Selenograph