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.

---

• 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.

[justinmk3]

The "endpoint override" here may help with:

• custom endpoints / Localstack #2007