Add getSearchParameter, a new method in YoutubeSearchQueryHandlerFactory class which returns the params field for a search, or an empty string if there is no one.
Update mocks of YoutubeSearchExtractorTest.
- Handle special cases for languages where the number is not shown
- Rework the Downloader base implementation, allowing for more
advanced things to be done
- Separate the localization from the content country (just like
YouTube let's the user choose both).