Add env variable for es.settings.index.nested_documents_limit to make it configurable with helm chart.

Testing Notes:

• CAMUNDA_OPTIMIZE_ELASTICSEARCH_SETTINGS_INDEX_NESTED_DOCUMENTS_LIMIT can be used to set the nested docs limit within ES
  • This can be tested in any environment
• Use an ES inspector to check the index settings and observe that the max number of nested documents matches what you set in the step above (the default is 10000, so you should use a different value to this)

QA Notes: 

We should check if the set nested docs limit can be seen in ES.

eg. "nested_objects": {"limit": "15000" }