Update beck-online.js

1. beck-online.js
Added support for beck-online "Leitsatzkartei" LSK (database of leading records), i.e. scraping of articles where beck-online does not have the article itself but only information about the article

2. juris
Added new translator for the German legal database Juris.
I can still access this one, so we can leave that be. If you can find more sources that can be accessed, feel free to add those test cases (particularly one including a date).