Make the new Torperf generate the new .mergedata output directly
Once we have finished #3283 (closed), we should get rid of the crazy separation of .data and .extradata files and just output a single .mergedata file ourselves. This output format could be like the one described in #3036 (closed). Implementing this ticket means rewriting most of the logic in
consolidate_stats.py, but the merging takes place live while measurements are running as opposed to offline. The output of all Torperf runs can go into the same .mergedata file; results can be attributed to a specific Torperf run by the contained meta data keys like FILESIZE, SOURCE, GUARDS, and CBT.
Once this ticket is implemented, we should consider closing #3036 (closed), too.
Assigning to tomb upon request.