move nominatim to preprocessing

[fhamborg]

we initially had the nominatim queries directly in the environment extractor, to spare some requests. however, as shown in https://github.com/bkrrr/Giveme5W/blob/master/extractor/extractors/environment_extractor.py we query each phrase that is a LOCATION so that we can for the sake of clean architecture perform the nominatim querying also in preprocessing.

[fhamborg]

i think there is no speed gain if (as it is now) thhe nominatim extraction is within the phrase extractor, because by definition the phrase extractor retrieves geopositions (using nominatim) for each NER. so why not move the whole extraction into the preprocessing, run it always, and also have it cached.

[fhamborg]

should be integrated with preprocessor_core_nlp.py