Added column "position" to system.columns and "column_position" to system.parts_columns

Return non-Nullable results from COUNT(DISTINCT)

Return NULL or zero when value is not parsed completely in parseDateTimeBestEffortOr* functions

Don't use debug info from ELF file if it doesn't correspond to the running binary.

remove unused imports from HTTPHandlerFactory

Skip empty URL parameters

Allow to drop table if there is no metadata in ZooKeeper; allow to rename.

Allow case-insensitive regexps; added a test

Remove trivial count query optimization if row-level security is set

This removes unused imports from `src/Server/HTTPHandlerFactory.cpp`:

```bash
- #include <re2/re2.h>
- #include <common/find_symbols.h>
- #include <Poco/StringTokenizer.h>
```

Fix nullable prewhere type

Minor modifications after merging #11554

Group by in order fix

* Update clickhouse-benchmark.md

Optimize doc translation for  Simplized-Chinese version,author by TomBombadil

* Update clickhouse-benchmark.md
Co-authored-by: NIvan Blinkov <github@blinkov.ru>

* Update lazy.md

Optimize the doc translation for Simplified-Chinese version.

* Update lazy.md
Co-authored-by: NIvan Blinkov <github@blinkov.ru>

Remove leader election, step 1: update and check version of "log" node

Avoid errors due to implicit int<->bool conversions when using ZK API