Change `list-scenes` defaults: don't output file, skip cuts

This would be a breaking change, but for v0.7 the default behaviour of `list-scenes` should be improved:

 - Replace `-n`/`--no-output-file` with a positive boolean flag `-s`/`--save`
 - Skip the cutting list as first CSV row by default, such that RFC 4180 compliance is the default
 - Rename `--skip-cuts` short option `-s` to `-c`