HTTP RequestLogger should accept io.Writer

[kylehuntsman]

The RequestLogger in the IPFS Handler should accept an io.Writer to allow for writing out to places other than stdout. This probably comes through all the way from the daemon CLI through an output flag that accepts a file location? There's a bigger conversation here around logging possibly going to stderr while CLI output goes to stdout by default. The daemon output flag would control the CLI output in this case.

[rvagg]

I have --log-file in frisbii for this, we should do the same with the daemon and it shouldn't be hard