[logstash] Add Statefulset Annotations through values.yaml

[loli71]

Hi,

Would be very nice to have metadata Customize deployment Annotations through values.yaml for logstash as mentioned #1790

• 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?

[cla-checker-service]

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