Introducing apply_to tags to the security privileges page (elastic#133622)

* Introducing apply_to tags to the security privileges page

The apply_to tags are the preferred way to signal when a setting is unavailable or has been deprecated.

Fixes [elastic#2215](elastic/docs-content#2215)

* trying to fix the build error

* Removed the verbose Serverless availability statements

* Missed one statement

* Adding more context around Serverless distinctions

* Minor edits -- peer review

* Fix link double brackets

Author: yetanothertw