Move OSM and personal data warnings

At the moment, the [``_warning_OSM``](https://github.com/InseeFrLab/pynsee/blob/c630e221ee4205e8df213ed8f6c1fb73fe96dc78/pynsee/sirene/get_location.py#L24) and [``_warning_search_sirene``](https://github.com/InseeFrLab/pynsee/blob/c630e221ee4205e8df213ed8f6c1fb73fe96dc78/pynsee/sirene/search_sirene.py#L18) functions are used to display warnings about legal implications.

This is probably not the best way to warn users and we should discuss how to handle it (probably in the docstrings and possibly also somewhere else in the README and/or the documentation).

EDIT: regarding SIRENE, it was decided to keep the warning in the code; for OSM, "info" logging level was used so it would be good to add the license information in the documentation and docstrings