[Request]: Document SLO Transforms and troubleshooting steps

[lucabelluccini]

Description

SLO hugely rely on transforms

• What are the built-in transforms and what they do
• Overall architecture to explain at high level the SLO<>Transforms relationship
• What are the additional transforms created, their naming and what they do
• How to understand if a transform is associated to SLO and if it is not healthy (as Transforms are not handled by o11y teams, we can link the platform docs)

Resources

We have an internal document (reach me out privately) with diagrams and troubleshooting steps. I think a part of this would be useful for users.

Which documentation set does this change impact?

Stateful and Serverless

Feature differences

None afaik

What release is this request related to?

N/A

Collaboration model

Other (please describe below)

Point of contact.

Request by @lucabelluccini

We need engineering to provide material and an overview.

[lucabelluccini]

Note https://github.com/elastic/kibana/pull/181351 is a good self-diagnostic step for the final user. It has been delivered in 8.15.0. The feature introduced to call out the health of the underlying Transform is great.