[REQUEST]: Document scaling options for each integration

### Description

## Description

We would need a new doc explaining how user can scale their integration horizontally by adding more agents or vertically by increasing resource for a given agent, depending on the integrations

### Resources

https://github.com/elastic/package-spec/issues/842#issuecomment-2521023199

### Collaboration

The documentation team will investigate the issue and create the initial content.

### Point of contact.

**Main contact:**

@nchaulet

**Stakeholders:**

@nimarezainia @lucabelluccini