Share Logging Code between restlogger and policy

Although policy uses az core policy and restlogger uses an http rountripper, they share a lot of code for logging the request/response. Change the code so that they are using shared functions to get the logging fields. Additionally, ensure that both have the same fields.

Locate the policy and restlogger implementations and compare how each builds request/response logging fields. Identify the duplicated logging logic, then confirm that shared functions provide the same fields for both paths; the issue provides no file or test names to run.

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