[Azure Logs] Add event hub sizing section in the integration logs

## Context

Event Hubs namespaces come in multiple tiers (Basic, Standard, Premium, and Dedicated) and capacity (TUs and PUs).

Each Event Hubs namespace has a fixed limit on the number of bytes and messages it can process in a given amount of time.

If users attempt to publish (via Diagnostic Settings) or receive (via Elastic Agent) more data than the Event Hub's capacity allows, the namespace will throttle the requests.

## Goal

Add a section to the Azure Logs integration docs [link] covering the following:

- Explain Event Hub tiers and capacity limits.
- Guide users on selecting the appropriate tier, capacity, and number of partitions.
- Detail how to detect throttling on the Event Hubs side using Azure Monitor.

## Impact

Proper Event Hub sizing enables users to set up stable and reliable ingestion systems (reducing support requests, too! ^^;)