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.
`^https?` definitely works. The rest of the regexp should also follow our "usual" practices, so `^https?://(www\\.)?juris\\.de/`