docs: Graceful shutdown for Envoy proxy

[davidalger]

Create design documentation covering graceful shutdown behavior as implemented in #2633 with example configuration to adjust any exposed knobs.

[github-actions[bot]]

This issue has been automatically marked as stale because it has not had activity in the last 30 days.

[davem-git]

This woujld be nice. I'm looking at how to do this. So far its not graceful by default. my tests show dropped connections when rolling restart with envoy gateway, but not with nginx ingress controller

[arkodg]

should be graceful by default, @davem-git can you create a new issue to describe how you are running your test and in which environment ?

[davem-git]

i created this https://github.com/envoyproxy/gateway/issues/4002