Safer auto-delete

Fixed

• The hourly cleanup only deletes a file itself while the bucket still has Aktar's rules, the file is still there and it wasn't uploaded again under the same name. Otherwise it just clears the history entry. After Turn Off and Remove Rules, files already under tmp/ stay for good, in history too.
• If a bucket's existing lifecycle rules can't be read completely, Aktar changes nothing instead of risking the bucket's other rules, and it checks the rules are really there after setting them up.
• Files moved or uploaded into a tmp/{N}d/ folder only count as expiring while the bucket has Aktar's rules.
• A rules check in a destination's settings no longer carries over to a different bucket, endpoint or region entered after it.
• Setting up the rules asks first when tmp/{N}d/ folders already hold files, since the bucket would start deleting those too. The help for adding the rules by hand now names the rule IDs Aktar looks for.