Standardize our configuration parameter docs to indicate ECE/Elasticsearch Service vs. on-prem support

From @jakommo:

> I’ve seen many issues where ECE customers tried to apply on-prem configs, because this was the first search result that came up on google. I was wondering if it would make sense to have both (ECE and on-prem) instructions on the same page, or at least add a note to on-prem docs with a link to the ECE config for this feature.

We probably don't want to merge these docs as they are today, but we should track the issue of how we can _improve the documentation of configuration parameters_ to indicate what they apply to, regardless of your entry point into the docs.

Among the issues that end up confusing customers today:

* We whitelist parameters for Elasticsearch Service and blacklist parameters for ECE. These are documented only in our cloud docs, but not, say, in our ES or Kibana docs. If you start in our cloud docs, you'll be mostly fine, although we don't document the blacklisted parameters exhaustively today. These docs to link to the ES or Kibana docs.
- People googling for content can easily end up on the ES or Kibana docs looking at a configuration parameter, with no indication that the parameter is not supported for our cloud products. They try it and

One proposal might be *to standardize how we document configuration parameters and add a field that indicates whether or not the parameter is supported on-prem, in ECE, or on the Elasticsearch Service*.

Source: https://docs.google.com/document/d/1iUZGa1K-wM5Fu4_Ho3Wep5MQyG-d47XJWve2oGcRyak/edit#bookmark=id.2f62wskyv2rk