[Serverless]: Add link to example of "process to automatically profile slow queries"

### Serverless Docs

Welcome to Elastic Serverless

### Description

The [Render pre-captured profiler JSON](https://www.elastic.co/docs/current/serverless/devtools/profile-queries-and-aggregations#render-pre-captured-profiler-json
) section of search profiler doc mentions the following:

_Sometimes you might want to investigate performance problems that are temporal in nature. For example, a query might only be slow at certain time of day when many customers are using your system. You can set up a process to automatically profile slow queries when they occur and then save those profile responses for later analysis._

We should consider adding a link to an example of a process that automatically profiles slow queries.

Alternatively, we can say _external process_ rather than just _process_. This way users don't assume there is a process to automatically profile slow queries built-in to the stack.

### Resources and additional context

- https://www.elastic.co/docs/current/serverless/devtools/profile-queries-and-aggregations#render-pre-captured-profiler-json