[client-v2] SSL Authentication

[chernser]

Summary

There is an option to use CN from client certificate to authenticate with a server. In this case next options should be set:

• username
• user certificate
• user key

Docs PR: ClickHouse/clickhouse-docs#2707

Closes: #1837

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

[sonarqubecloud]

Quality Gate failed

Failed conditions
69.1% Coverage on New Code (required ≥ 80%)

See analysis details on SonarCloud