[Azure docs] Add a new use case on how to collect any metric using the Azure Monitor

[alaudazzi]

Description

Now that the existing Azure tutorials have been refactored under the new Azure monitoring section, we can add a new use case on how to collect any metric using the Azure Monitor.

Relates to https://github.com/elastic/observability-docs/issues/3742

Resources

• Some draft content is available in Figure out how to collect any metric using the Azure Monitor integration zmoog/public-notes#69
• Original GH issue: [Azure docs] Document how to collect any metrics using the generic Azure Monitor integration integrations#8849

Which documentation set does this change impact?

Stateful and Serverless

Feature differences

None

What release is this request related to?

N/A

Collaboration model

The documentation team

Point of contact.

@Maurizio