Reduce accuracy GeoIP

[antoinehashbang]

• Remove region and city from Activation model
• Generate migrations and add SQL to update existings rows and add constraints on latitude and longitude
• add validation on latitude and longitude on Activation model
• Add tests

https://phabricator.endlessm.com/T31730

[dbnicholson]

Looks like the test is failing:

self = <azafea.event_processors.endless.activation.v1.handler.Activation object at 0x7fcb0629f850>
key = 'latitude', latitude = 14.3

    @validates('latitude')
    def validate_latitude(self, key: str, latitude: Optional[int]) -> Optional[int]:
        # Catch both None and the empty string
        if not latitude:
            return None

        if math.floor(latitude) + 0.5 != latitude:
>           raise ValueError(f'latitude is not an integer + 0.5: {latitude}')
E           ValueError: latitude is not an integer + 0.5: 14.3

azafea/event_processors/endless/activation/v1/handler.py:76: ValueError