gfio: Add support for sending logs over the network

gfio: Add support for sending logs over the network

This is for things like bw log, latency logs, etc. We add
a new depedency, zlib, for this. The logs can be quite big and
the network is not necessarily super fast, so we compress them
using zlib.

Signed-off-by: Jens Axboe <axboe@kernel.dk>