Add a Descriptor subinterface and implementation for Tor web server logs
The webstats-log-files are the only files available on CollecTor (in future) that are not yet covered by metrics-lib.
Should there be a 'LogDescriptor' interface and implementation in metrics-lib? Are there any reasons why not?
LogDescriptor is just a working name; better naming suggestions welcome.
The interface should extend
Descriptor and have additional methods for retrieving the measuring host and the served host, a method for retrieving the date of the log.