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.
Let us add here an example in the code, e.g. `//e.g. src = "Leisterer, Schneider, CR 2014, 574"`