Consider bringing back `silent` config option to silence console.logs.

[jamischarles]

3.x had a silent cfg option which would supress console.logs. A lot of our tests end up printing a ton of console logs that would be great to be able to easily suppress w/o having to mock or override console.log:

https://github.com/krakenjs/beaver-logger/blob/3.x/client/logger.js#L180-L182

Can we consider bringing that option back? @westeezy