configure log level - decrease current output

[mvdbeek]

Running planemo on the command line will produce a lot of output into stdout, which make it really hard to find errors. Would be great if we decreased the amount of output or provide templates configurations for decreasing log level without losing important information.

[mvdbeek]

This is @Smeds's issue. I think #1510 is largely addressing this, but I think a verbosity flag might make sense that controls the log level