Reintroduce 96111: Provide guidance of "Custom" allocation behavior in ILM (#99007)

[cjcenizal]

Backports the following commits to 7.x:

• Reintroduce 96111: Provide guidance of "Custom" allocation behavior in ILM (Reintroduce 96111: Provide guidance of "Custom" allocation behavior in ILM #99007)

[spalger]

Just want to make sure that #99108 is merged before this

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 9167556
• Storybooks Preview

Metrics [docs]

Module Count

Fewer modules leads to a faster build time

id	before	after	diff
indexLifecycleManagement	206	211	+5

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
indexLifecycleManagement	247.1KB	248.8KB	+1.8KB

Page load bundle

Size of the bundles that are downloaded on every page load. Target size is below 100kb

id	before	after	diff
indexLifecycleManagement	50.1KB	50.3KB	+189.0B

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream