Extend MMDB with max_country_info_qt

[cudeso]

When querying MMDB there are sometimes multiple country_info objects returned, mostly due to the different db_source. Sometimes customers are not interested in the db_source, and only the geo-info. This change adds max_country_qt. When

• Set to None or 0, has no effect
• Set to a value higher than 0, the number of country_info entries is limited to max_country_info_qt