docs: add Azure RBAC role assignment best practice for Azure Key Vault

[maor-klir]

Reason for Change:

Improves documentation and follows Microsoft's recommendation for improved security when managing an Azure Key Vault

Requirements

• squashed commits
• included documentation
• added unit tests and e2e tests (if applicable).

Issue Fixed:

Please answer the following questions with yes/no:

Does this change contain code from or inspired by another project? If so, did you notify the maintainers and provide attribution?

• yes
• no

Notes for Reviewers:
Added documentation and code snippets

[Copilot]

Pull request overview

This PR enhances the Azure Key Vault documentation by adding Microsoft's recommended Azure RBAC permission model alongside the legacy access policy approach, improving security guidance for users.

Key Changes

• Adds Microsoft's official recommendation to use Azure RBAC instead of legacy Key Vault access policies
• Provides complete Azure RBAC code examples for both Azure AD Applications and User-Assigned Managed Identities
• Maintains backward compatibility by keeping legacy access policy examples with clear labels

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[maor-klir]

Hi code owners (@aramase, @enj, @stlaz),

Just a friendly ping that this PR is ready for a final review.

Thanks!

[aramase]

Thanks for the PR!

The better approach is to remove the legacy access policy commands and instead document using RBAC to access Key Vault in the quick start.

[maor-klir]

Thanks for replying, I have followed your suggestions

[maor-klir]

Hi @aramase , could you please have a look?
I have made the necessary changes, thanks