Deprecate VisualStudioCodeCredential

[scottaddie]

Ask: Deprecate VisualStudioCodeCredential (along with VisualStudioCodeCredentialOptions and the supporting @azure/identity-vscode plugin package). There's no path to success when using it. Also, remove all mentions of the credential from the README.

Background: The VS Code Azure Account extension on which VisualStudioCodeCredential relies has been deprecated. Customers should use other dev-time credentials, such as AzureCliCredential, for their local development needs. Once the VS Code desktop app has authentication broker support (via MSAL Node.js) across Windows, macOS, and Linux, a broker-enabled instance of InteractiveBrowserCredential would be a great solution here. Unfortunately, that broker support only exists for Windows customers today, via WAM. Issue #33293 tracks the work to improve the devex for VS Code customers on Windows.

[github-actions]

@KarishmaGhiya @maorleger

[github-actions]

Thank you for your feedback. Tagging and routing to the team member best able to assist.