Wrap directory watcher from birdnetlib

[MaHaWo]

Is your feature request related to a problem? Please describe.
Currently we have no automated way to watch a directory for incoming files and do the analysis for it. Rather, we can only load individual files and need to do while... manually.

Describe the solution you'd like
birdnetlib implements a solution that we can either use directly or wrap into something we would like.

Describe alternatives you've considered
Write everything ourselves from scratch, which isn´t a good first solution obviously.