Add LogLevel Hooks to HttpLogOptions and HttpLoggingPolicy

[alzimmermsft]

Fixes #11477

This PR adds two new interfaces HttpRequestLogger and HttpResponseLogger to handle logging requests and responses in HttpLoggingPolicy. The interfaces function similarly where they have a method that determines the logging level for a request/response and a method that logs the request/response if the ClientLogger is capable of logging at the expected logging level.

HttpLogOptions has been updated with two new getters and setters to configure the HttpRequestLogger and HttpResponseLogger that will be used by HttpLoggingPolicy. Each property will have a default if it isn't set which is the current logic that HttpLoggingPolicy uses, LogLevel.INFORMATIONAL for default log level and its implementation functions for logging requests and responses.

With the new changes HttpLoggingPolicy can be configured to log with specific goals in mind, the following are a few scenarios:

• When responses take longer than expected to return the log level for the response can be escalated. For example, if the response takes more than 5 seconds to return it will be logged at the warning level, if the response takes more than 15 seconds to return it will be logged at the error level.

• You have a nightly job which copies log files from your application servers and performs processing on the logs. This requires specific information to be logged in a well known format. The request and response logging functions can be customized to ensure the logging format complies with the processing requirements.

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