Introduce logger

[mmacata]

This PR introduces a logger. By default it prints logs to STDOUT in JSON format. It is not configurable yet but if this is needed it can be done in a separate PR.

One example log is integrated in collections.py. The line log.warning("Couldn't get STAC collections from actinia") will look like the following in the STDOUT log output:

{"time": "2021-11-19T16:50:00.811279Z", "level": "WARNING", "component": "openeo-grass-gis-driver", "module": "collections", "message": "Couldn't get STAC collections from actinia", "pathname": "/src/openeo_grass_gis_driver/src/openeo_grass_gis_driver/collections.py", "lineno": 97, "processName": "MainProcess", "threadName": "Thread-10"}

Depending on deployment, simple print statements are not visible in STDOUT/collected for docker logs. These print statements were adjusted in this PR as well.
This also helps for integration with logging tools like e.g. Kibana when deployed in a cloud environment.

[metzm]

Looks good to me.