Implement Wikipedia TV brand hierarchy adaptor

- Includes asynchronous fetching method (FetchMeister)
    - Movie adaptor should perhaps be altered to use it too
Implement SwebleHelper.extractDate(...)

Now we try to interpret date templates! This allows:
    - Extracting air dates of episodes
    - Extracting run dates of brands
Handle shows without season sections in their articles
Calm down date extraction error logging and fix imports
Extract IMDB aliases for TV brands