## Problem
It's hard to find out which DB size we use for OLAP benchmarks (TPC-H in
particular).
This PR adds handling of `TEST_OLAP_SCALE` env var, which is get added
to a test name as a parameter.
This is required for performing larger periodic benchmarks.
## Summary of changes
- Handle `TEST_OLAP_SCALE` in
`test_runner/performance/test_perf_olap.py`
- Set `TEST_OLAP_SCALE` in `.github/workflows/benchmarking.yml` to a
TPC-H scale
Add ClickBench benchmark, an OLAP-style benchmark, to Nightly
Benchmarks.
The full run of 43 queries on the original dataset takes more than 6h
(only 34 queries got processed on in 6h) on our default-sized compute.
Having this, currently, would mean having some really unstable tests
because of our regular deployment to staging/captest environment (see
https://github.com/neondatabase/cloud/issues/1872).
I've reduced the dataset size to the first 10^7 rows from the original
10^8 rows. Now it takes ~30-40 minutes to pass.
Ref https://github.com/ClickHouse/ClickBench/tree/main/aurora-postgresql
Ref https://benchmark.clickhouse.com/
