The recovery process need some more attention. For now, no way to
reproduce recovery fail, because data files are changed by recovering &
nothing to analyze at the end.
I want to change it:
1. As configurable option. Copy data file before recovering. That will
leave data as it is & information to analyze.
2. Again, as configurable option. If recovering failed, delete data (if
option 1 disable copy&delete?) -> run fresh eXist -> restore from last