deps(sdkv3): implement logging and endpoint override for client builder.

[Hweinstock]

Problem

The V3 client builder currently only adds telemetry. We want some additional functionality on each request/response.

Solution

• Allow user to override the endpoint used by the sdk.
• Add debugging messages for each request and response.

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• Treat all work as PUBLIC. Private feature/x branches will not be squash-merged at release time.
• Your code changes must meet the guidelines in CONTRIBUTING.md.
• License: I confirm that my contribution is made under the terms of the Apache 2.0 license.