Add a silent or log-level option for the CLI

[maastrich]

Problem Description

Hello there, I've setup lingui in a project that has a lot going on, running test or build can be a little verbose so it is kind of painfull alway searching the output to see what my problems are.

Proposed Solution

It would be nice to have a --silent option to hide any output (except for errors)

Alternatives Considered

I could redirect to /dev/null or even a log-file but I don't feel like it would be the right solution

Additional Context

If you feel like this could be a nice feature but do not want to waste time on it, let me know, I could open a pull request

[timofei-iatsenko]

You can open a PR