Allow the OkapiClient to try to communicate with compressed data

During integration testing, we found that when edge-patron communicates with mod-patron, headers are sent as is from the client. One header, Accept-Encoding caused mod-patron to compress its responses, which edge-patron proxied back to the client, but without encoding headers.

Instead of trying to manage this in edge-patron, where we'd need to know how to decompress the message, we will let Vert.x handle this by setting the HttpClientOption tryUseCompression, which will manage all compression details for the module.