Add more output details for debug purposes

[ribalba]

Currently we don't really have a way to add debug output to our code that is only outputted when run with --debug or sometimes I would also want to have less output. I would like the functionality to add some logging to my GMT code that is only outputted when run with --debug.

I would propose to change all print statements with an actual logger. So we can have different verbosity levels. As we don't have discussions I am using a ticket :)

[ribalba]

From @ArneTR
I guess the sane place to add it to would be "Logs" Tab, as in example here: https://metrics.green-coding.berlin/stats.html?id=9d250a5f-1f01-42a2-926e-e3f9b216ed5a

Just the prints from the GMT should be logged separately and then just added to self.__stdout_logs

[ribalba]

I would also want different "levels" like INFO, DEBUG, ...

[djesic]

I have this logging library starred: https://github.com/Delgan/loguru
And this one is very helpful for debugging https://github.com/samuelcolvin/python-devtools