[Suggestion] Workarounds for case-insensitive exceptions use cases

### What can we change to make the docs better?

We have [this docs page](https://www.elastic.co/guide/en/security/current/add-exceptions.html) that mentions that exceptions are case-sensitive and suggests only one workaround:

> Rule exceptions are case-sensitive, which means that any character that’s entered as an uppercase or lowercase letter will be treated as such. In the event you don’t want a field evaluated as case-sensitive, some ECS fields have a .caseless version that you can use.

But there are many other workarounds that our users could use and should know about. It would be great to document them on a single consolidated page, so that our users don't have to learn the whole Elastic stack to come up with this list themselves.

[This list](https://discuss.elastic.co/t/elasticsearch-shared-exception-lists/373456/2?u=georgii) of workarounds could be used as a starting point for collecting and documenting all of them.

### Doc URL

Doc URL: https://www.elastic.co/guide/en/security/current/add-exceptions.html

### Which documentation set needs improvement?

ESS and serverless

### Software version

N/A