[filebeat] Add extraInitContainers to filebeat chart

[vasrem]

• 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

Please let me know if there is anything more I should add in the PR.

[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]

Author of the following commits did not sign a Contributor Agreement:
fbf6249

Please, read and sign the above mentioned agreement if you want to contribute to this project

[cla-checker-service]

Author of the following commits did not sign a Contributor Agreement:
fbf6249, f114e2a

Please, read and sign the above mentioned agreement if you want to contribute to this project

[vasrem]

I've already signed the CLA. Could you please have a look at the PR?

[jmlrt]

⛴

[jmlrt]

jenkins test this please