Guided UI for updating managed ILM policies (usually associated with packages/integrations)

[andreidan]

Describe the feature:
We have managed index templates and ILM policies shipping with fleet integrations/packages.
It's very common for users to want to modify the ILM policies for the integrations and we have
a couple of tutorials on how to achieve this that involve cloning the managed ILM policies manually,
making the changes, updating the @custom component template. Namely:

• https://www.elastic.co/guide/en/apm/guide/8.11/ilm-how-to.html
• https://www.elastic.co/guide/en/fleet/8.11/data-streams-ilm-tutorial.html

(note that both tutorials are missing a step to point the existing backing indices to the new/
clone ILM policies - elastic/apm-server#12166)

This is a very common operation as users would want to take advantage of tiers, searchable
snapshots, and add/modify the retention.

This proposes we create a UI that is aware of integrations/packages and allows our users
to easily implement the tutorials linked above.

[elasticmachine]

Pinging @elastic/platform-deployment-management (Team:Deployment Management)

[axw]

I don't know if we should bundle this in here or consider it a separate issue, but I'd also want the same for Data Stream Lifecycle management. We'll probably switch to DSL by default in the future for APM.

[elasticmachine]

Pinging @elastic/kibana-management (Team:Kibana Management)