Update colombia scraper to no retry after a 404 error

[yolile]

The Colombia API changed and now if a link returns 404 it means that there are no more pages
We can update the API to include from_date parameter too

[jpmckinney]

Let's reuse (or improve) the logic in BaseSpider for setting the default from/until date, instead of having that logic in the individual spider. The Colombia spider should just be concerned with setting the date_format class variable and with calling strftime.