Implement a logging mechanism which scrapers were used

[Former user]

Reported by dbe: Please implement a logging mechanism which allows us to trace which scraper was used how often (by external users and by ourselves). It would be good to get this information in a summarized form e.g. once a day via email.

It is probably best to implement most of this in

org.bibsonomy.scrapingservice.servlets.ScapingServlet

Please don't add too much overhead, something like a in-memory hashmap whose values can be retrieved (and reset) via a certain URL is probably already enough.

[Daniel Zoller]

please do not use ScapingServlet. some controller are using the scraper chain