Fix distance evaluation client
- Fix owner key retrieval in distance client
- I could not find how to decode the StorageMap cleanly so I used byte ranges with the help of this article. I'm not sure it can't break in the future.
- Fix modulo in evaluation result filename in distance oracle
- Fix evaluation result file deletion
- If you want to name the files using pool indices instead of a strictly increasing sequence, you run into problems (this is the reason why it was not the case, btw). It should work now, but if the node can't publish (i.e. crash or network error for this block) after the file is deleted, the evaluation result is lost.
Fixes #261