fix(logger): use name instead of file for logger base

[peckto]

Fixup for #556
Unfortunately, __file__ does not work, because it returns the full path to the source file (eg. /path-to-venv/gallia/...) and the logger name is expected to be a dot-separated tree with gallia as base (because we filter on that).

I propose to use the __name__ variable for the logger name, it starts with gallia..

[ferdinandjarisch]

As said, I didn't test #556 but yeah, __name__ is what I had in mind, as this is what python's logging docs are suggesting to use!