Fix SchemaRuleCommand parser for 2.1
Test index counts are built correctly when migrating from 2.1 and 2.0
Remove BYTES_AS_INT use BYTES with proper min and max constraints instead
Add a test to make sure counts are propagated correctly in HA
Create a package for CountsKey and friends

- introduce a Factory for creating CountsKey
- make CountsKey to be an interface rather than an abstract class
Unify API on CountsStore to always use registers

- add a 'satisfies' method to the CopyableDoubleLongRegister to simplify assertions
Merge pull request #3416 from davidegrohmann/2.2-migrate-counts-it

More tests and code cleanup related to IndexSelectivity