- [x] remove multiprocessing - [x] fix logging, output and cache policies - [x] errors must be logged only when something's gone wrong, and not simply when a match cannot be found or searched for whatever reason (in such cases, a warning must be logged instead) - [x] snapmatcher should always return a json output, even when a match cannot be searched or found - [x] pool cache must be used if user settings mandate it, but csv stats should be generated in any case - [x] use aliases in package name matching - [x] download debian source files - [x] return `debsrc_origin`, `debsrc_debian` and `debian_format` as the `match` command (such data are needed for subsequent commands of a4f workflow)