Document how to found out where to report issues with packages

The idea is to document a way for users to found out to which package specific file belongs to and how to found out where to report issue. The idea is to lower issues reporting for packages that are not maintained by use at all but rather by upstream. It is possible to do that by looking at Maintainer field of package and if there is CZ.NIC then it should be reported to us, otherwise in general it should go to upstream.