A/B testing - E vs C and C vs E

[nablaone]

This PR contains:

• generalized code of A/B testing query results for both scenarios: Elastic vs Clickhouse and Clickhouse vs Elastic
• kibana dashboard id is stored in a separate column
• we don't store requests and A/B responses if the responses match

Some code is copy pasted. I'm not brave enough to generalize it now.

Tests will be added as part of IT suite.