Add OVHcloud AI Endpoints documentation

[eliasto]

Description

This PR introduces the documentation for the integration of OVHcloud AI Endpoints inference provider. It follows the PR done in the python-sdk repository: strands-agents/sdk-python#1172

Type of Change

• New content addition
• Content update

Motivation and Context

This PR is needed for the introduction of the new model OVHcloud AI Endpoints, to guide user on how to use it.

Areas Affected

• user-guide/concepts/model-providers/ovhcloud
• api-reference/models/#strands.models.ovhcloud
• user-guide/quickstart/#model-providers

Checklist

• I have read the CONTRIBUTING document
• My changes follow the project's documentation style
• I have tested the documentation locally using mkdocs serve
• Links in the documentation are valid and working
• Images/diagrams are properly sized and formatted
• All new and existing tests pass

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.