Update graceful shutdown from 300 to 1800 seconds

[joshuacolvin0]

There are a few places where 300 seconds is recommended as the graceful shutdown value (5 minutes). Since busy nodes or nodes or nodes running on slower storage volumes can take longer than 5 minutes, 1800 seconds is a better value (30 minutes). Usually the nodes will shutdown long before 30 minutes, but the longer graceful timeout will ensure that nodes don't get killed before finishing a graceful shutdown

[pete-vielhaber]

I believe I found all the mentions and opened a PR 2123

[pete-vielhaber]

merged