Move _report directory

[nichtich]

The _report directory inside the input directory should be moved because the input may be read-only and because the reports are actual logfiles of running qa-catalogue so they should better be in a logfile location. Possible places:

• logs/ (parallel to input and output) - that's what I would prefer. Possibly configure with environment variable LOGS like INPUT and OUTPUT can be configured.
• output/logs/ (could clash with catalogue of name logs) or output/$NAME/logs/