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 liked @zuphilip's suggestion of just adding some actual sample data in the comments. With complex regexps it's very helpful (I'd add one sample with and one without the date)