[fix] Namespace issue in AbstractScraper

The constructor was looking for a `DocumentProvider` class in its own namespace instead of referencing the proper one.
Extract DocumentProvider getter to abstract class
[doc] Fix namespace in docblock

Sometimes, I’m just stupid.
Make K/MPList scraper extend AbstractScraper

Remove the property, since it’s now already created through the parent class.
Update the constructor so that it calls the parent one before doing any specific work.
Extract `newCrawler()` method to AbstractScraper
Make S/MPList scraper extend AbstractScraper