Added the `log_request_response` and `log_request_response_max_size`
options to osh-http-proxy.conf.
By default, requests are logged, including their body, up to a size
of 64K per request response. Before, there was no size limit to the
logged body response.
The following additional header is now allowed to come back from the remote server to the client:
* Content-Length
The following additional headers are now passed through to the remote server:
* Content-Length
* Content-Encoding
