write proper docs
Jerry pointed out that respdiff.cfg needs more docs, especially when it comes to:
- which sections affect what tool
- what criterias and weights exists and what they do, how they match etc.
Match description can be mostly copied from https://gitlab.labs.nic.cz/knot/deckard/blob/master/doc/scenario_guide.rst#id1
Mapping config section to names is not straightforward as I thought because
[diff] section configures
[msgdiff] tool and
diffrepro as well.