Add a new configuration to convert things to scope

[ArcturusZhang]

Regen: Azure/azure-sdk-for-net#33745

Description

This PR adds a new configuration to allow you to mark a specific request path as a "scope" with a certain resource type.

For more details about this, please check the new doc changes in this PR.

This PR also fixes a using issue when the samples invoke the extension methods (added the missing using statement)

Checklist

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