Allow User defined configurations in values.yaml for Kibana resource

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

Acceptance Criteria:

1. The new implementation should allow configuration from the user
2. It should be backward compatible and allow for defaults configuration (possible implementation is a .tpl helper)