Allow for Templating of the Elasticsearch Resource Config

Feature Request

Why

The config specs of the elasticsearch resource is vital for allowing modifications including storage changes. Currently the Big Bang managed Elasticsearch resource has the configs hardcoded, which means customers have to either fork the repo to make changes, add a postrenderer to modify.

Proposed Solution

We should allow config changes from the values.yaml. This implementation should be similar to the mimir config approach with the templating available through values.yaml, see mimir values.yaml structuredConfig reference.