KIC 2.0: handle update-status and update-status-on-shutdown flags

[rainest]

--update-status enables or disables the Ingress status update background job.

--update-status-on-shutdown enables or disables Ingress status updates by the leader when it is shutting down. It is enabled by default. The 1.x implementation had known issues.

In 1.x, these updates populate address information for Ingress objects (i.e. the value shown in the ADDRESS column when you run kubectl get ingress). 2.x reworks status handling significantly.

Low priority since toggling status updates off isn't a critical feature.

[shaneutt]

I have re-enabled --update-status but I can see no value in maintaining the --update-status-on-shutdown. KIC 2.0 has no other mechanisms for cleanup on shutdown, and in fact the re-entrant nature of the current design is meant to account for "cleanup". As such I have made a PR which proposes deprecating the second flag given that it conflicts with the direction we're going with KIC, and seems to be of dubious value (whereas conversely --update-status is of obvious value).

[sephethus]

That's fine, nobody knows where to put that flag anyway because it's not like there's examples or documentation.