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.
deprecated and also doesn't seem to be necessary given below. Also, not quite sure what the purpose of this function is in general. Just use `ZU.xpathText` in the code below.