Add new schema validation feature and enhance table schema retrieval

[amolsr]

Summary

closes #610

Checklist

Delete items not relevant to your PR:

• Unit and integration tests covering the common scenarios were added
• A human-readable description of the changes was provided to include in CHANGELOG
• For significant changes, documentation in https://github.com/ClickHouse/clickhouse-docs was updated with further explanations or tutorials

[chernser]

Good day, @amolsr !
Thank you for the contribution!
I will review this week.

[chernser]

@amolsr

I've updated #610
Current PR doesn't close the issue. We need first of all create a good suit of tests. It may be a few consequent PRs.
Then we need to estimate the effort of bringing client's approach of reading table schema:

1. would it be easy to have old and new approach at the same time. how much code should be adopted.
2. should we just take ClickhouseColumn and integrate with existing code?

I suggest closing this PR and starting with tests. Currently I may not accept it anyway, sorry.