feat(regionserver): add graceful shutdown configuration #1960

Job	Run time
Check if committed README is the one we would render from the available parts	22s
Run Cargo Deny (advisories)	39s
Run Clippy	32s
Check if committed Helm charts are up to date	40s
Run Cargo Deny (bans licenses sources)	42s
Run RustDoc	1m 0s
Run Rustfmt	11s
Run Cargo Tests	27s
Select target helm repository based on action trigger	1s
Run Cargo Udeps	1m 23s
All tests passed	1s
Package Charts, Build Docker Image and publish them - ubuntu-latest	10m 6s
Package Charts, Build Docker Image and publish them - ubicloud-standard-8-arm	9m 29s
Build and publish manifest list	38s
Run the OpenShift Preflight check on the published images	20s
	26m 31s

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