Additional Kibana Reporting diagnostics

Similar to https://github.com/elastic/support-diagnostics/issues/676, there are additional diagnostics which would be useful to collect as part of the Kibana Reporting diagnostic stats.

This information is probably found in parts of the Elasticsearch diagnostic bundle, but it would be helpful for the Kibana Platform Engine team to find this information in the Kibana Reporting diagnostics as well.

### 8.15+
For stack versions 8.15 and higher, it would be useful to collect:
* Check for the existence of the `.kibana-reporting` template
* Details of the component templates: `kibana-reporting@settings` and `kibana-reporting@custom`
* Details of the `kibana-reporting` ILM policy (or any retention policy that is set on the data stream)
* Whether refreshes are enabled on the data stream
* Check the `stack.templates.enabled` flag in Elasticsearch

### Any version
For any stack version, it would be useful to collect:
* The value of the `http.max_content_length` setting