Changes around votes, including HF26 features
HF26 features included in this MR are:
- votes no longer have 3s cooldown - the same voter can vote many times in the same block
- vote edits are no longer penalized with no curation rewards - they behave mostly as if the original/previous vote was not there
- dust votes are fully considered as votes - it will no longer be possible to use operations that require no votes to be performed when comment received dust votes
On top of that MR contains some minor optimizations and fixes in tests on votes (and new tests to cover above features). See commit history for details.