Compress end user CSS

__Is your feature request related to a problem?__

Not related to a problem, more of an improvement.

__Describe the solution you'd like__

I would like prop on `JssProvider`, which has a side effect to override the modification of the end CSS from `react-jss` output. By default behaviour to `NODE_ENV` (e.g. `development` === `verbose`).

__Are you willing to implement it?__

It depends on the breadth of the change, I am not too familiar with the required changes. But happy to start a conversation. I have little time available but can try and contribute back.

__Managing expectations:__

It would be great to have a manual override to either leave the compiled CSS as verbose or compressed. The change would require, little long term energy in maintaining.