Bug: fix bug in snapshot selection queries and enhance rollback queries

[iltoga]

Description

Actual selection criteria for snapshots is wrong and all queries need to be refactored to fix the issue.
Moreover, applying part of the fix to rollback queries, we will increase their performance, thus including the enhancement in this bug fix issue.

Steps to reproduce

1. Run a node till it generates a snapshot
2. run a second node and verify that most of the time that node can't go on smithing because it doesn't have the same node_registry as the first one

Expected behavior

After starting from a snapshot, a node should be able to download new blocks