graceful termination handler for master nodes

[kimxogus]

Rewrote #108 with reference #63 (comment)

fixes #63 for all es versions!

• Chart version not bumped (the versions are all bumped and released at the same time)
• README.md updated with any new values or changes
• Updated template tests in ${CHART}/tests/*.py
• Updated integration tests in ${CHART}/examples/*/test/goss.yaml

[elasticmachine]

Since this is a community submitted pull request, a Jenkins build has not been kicked off automatically. Can an Elastic organization member please verify the contents of this patch and then kick off a build manually?

[Crazybus]

I suggested a few minor tweaks. Apart from that this is looking fantastic! I tested it out and it is working exactly as expected!

Thank you again so much for your persistence in getting this working :)

[kimxogus]

Applied changes

[Crazybus]

jenkins test this please

[Crazybus]

build failed because of google storage failures (even with retries):

curl: (7) Failed to connect to 2607:f8b0:4001:c14::80: Cannot assign requested address
The command '/bin/sh -c curl --retry 5 -O https://storage.googleapis.com/kubernetes-helm/helm-v${HELM_VERSION}-linux-amd64.tar.gz &&     tar xfv helm-v${HELM_VERSION}-linux-amd64.tar.gz &&     mv linux-amd64/helm /usr/local/bin/ &&     rm -rf linux-amd64 &&     helm version --client' returned a non-zero code: 7

jenkins test this please

[Crazybus]

LGTM!

Thank you again so much for your persistence in working on this!

[tetianakravchenko]

@kimxogus @Crazybus is this additional container needed for all versions? as I understand it should be fixed as mentioned #63 (comment), maybe it makes sense to introduce additional value and add this container optionally? wdyt?