Add quiet mode

[adiroiban]

codecov run is pretty verbose (including the big ascii art )

when reading the CI logs, is inconvenient to ignore all the codecov output ... and with lots of logs it increase the size of all the logs store on disk.

It would be nice to have a quiet mode, which will output a single line.

If there are issues, users can temporary enable the current "debug" mode.

Thanks!

[stevepeak]

Sure :) Thank you for the feedback. We welcome pull requests if you feel inclined to contribute.