fix(core-database): straight delete blocks during rollback

[rainydio]

Summary

Blockchain.removeTopBlocks now calls BlockRepository.deleteTopBlocks instead of loading them first through DatabaseService.getTopBlocks and then deleting through BlockRepository.deleteBlocks.

Note that previously Blockchain.removeTopBlocks was eating error, only logging it instead of re-throwing.

There are two use-cases when blocks have to be deleted:

1. During rollback top 1000 blocks (up to 10000) are removed.
   Improved by this PR.
2. When reverting, reverted blocks are deleted at the end.
   I plan to refactor revertion to use new BlockRepository.delgetTopBlock that pops single block from database rendering BlockRepository.deleteBlocks obsolete.

Checklist

• Tests
• Ready to be merged