[Request]: Update EEM docs to reflect new inventory

[roshan-elastic]

Description

We need to update the EEM docs to reflect that they will now:

a) include more entities than just services (e.g. hosts and containers)
b) the new service inventory is going to be merged into the new inventory - we can just remove references to the 'new service inventory' and instead mention the 'new inventory'

Notes

• This go live in serverless on 7th Oct

Resources

• https://github.com/elastic/observability-dev/issues/3882)
• [Request]: Create new inventory docs and remove docs for new service inventory #4254

Which documentation set does this change impact?

Stateful and Serverless

Feature differences

Identical in stateful/serverless

What release is this request related to?

8.16

Collaboration model

The documentation team

Point of contact.

Main contact: @chrisdistasio

Stakeholders: @smith

[roshan-elastic]

@chrisdistasio - I put you as the owner on this as I figured it made sense. That OK?

[smith]

Added this as a dependency on https://github.com/elastic/observability-dev/issues/3882.

[chrisdistasio]

@roshan-elastic is this still planned to go live on 7 October?

[chrisdistasio]

proposed updates

[alaudazzi]

Doc updates ready for review in #4340

[roshan-elastic]

Hey @chrisdistasio - should be yes! Is there a cut off date for when things need to be merged into main to go into serverless?

@kpatticha - Do you know when we'll be merged into main for everything?

Context : Want to confirm if we'll be in serverless for the 7th Oct release