[Suggestion] Clarification on using rules in different spaces

[maximpn]

What can we change to make the docs better?

We need a separate page describing how spaces allow to isolate source events, security rules and generated alerts via Kibana spaces. There is no such a page but users periodically ask about such a page like here. It'd be nice to elaborate on Garrett's response.

Doc URL

Please include the doc URL and any other related information where applicable:
Doc URL: we need a new separate page
Github issue link(s)/Other resources:

https://discuss.elastic.co/t/kibana-security-elastic-rules-space-issue/301861
https://discuss.elastic.co/t/clarification-on-rules-execution/368073
https://discuss.elastic.co/t/warning-in-rules/290036

Which documentation set needs improvement?

ESS and serverless

Software version

Currently Serverless doesn't support spaces but it should appear soon. It's good to have documentation for both.