Allow http request response tracing

[davidradl]

After feedback on apache/flink-connector-http#5 and further thinking in IBM and in response to the Flink feedback, we are suggesting default no sensitive data but allow more tracing to be enabled. With a config of

http-request-response-logging, that has 3 values

min- the default, no content from requests responses and headers.
reqresps - requests and responses
max - requests, responses and headers